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1. On the lower Greensand and Gault of Folkestone
F. G. H. PRICE ON THE LOWER GREENSAKD, &0.
185
The following were elected Members of the Association : Baron de la Taille des Essarts; Esq. j and John T. Young, Esq.
Francis Robert Morrison,
The following Papers were read : -
1.
ON THE LOWER GREENSAKD AND GAULT OF FOLKESTONE.
By
F. G.
H.
PRICE, ESQ., F.G.S., F.R.G.S,
M.A.I.
It is my intention this evening to lay before you a sbort account of' the Upper Neocomian and Gault of' Folkestone, than which place I mllY remark, for the benefit of those who happen to be unacquainted with the district, there is..no better locality on the south-east coast of England for the student of Cretaceous geology. If he makes that interesting old town his head quarters, he can take some most valuable and instructive rambles into the surrounding district, where fine and extended sections of all the various stages of the Cretaceous beds, from the Wealden, west of Hythe, to the Upper Chalk, near Dover, can be found. THE LOWER GREENSAKD.
The town of Folkestonc is situated upon the Folkestone Beds of the Upp er Neoeomian, In order to find the base of the Upper Neocomian series, we must go to Aldington Knowl, situated about five miles westward of Hythe, where the Atherfleld Clay forms a long inland cliff extending to Hythe, but, as we are informed by Mr. Drew, F.G.S., in the" Memoirs of the Geological Survey," the beds of the Kentish Rag have slipped down and covered it up, consequently it is seldom seen. It is about 30 feet in thickness, and may be seen at very low water on the shore ncar Shornc1iffe Battery. The Hythe Beds likewise make their first appearance at Aldington Know1; the lower ground to the south being occupied by the W cald Clays j very fine sections of the Hythe Beds or Kentish Rag may be seen in the quarries at the back of the town of Hythe, from whence the Rag-stone is extracted largely for building. It is a Iimestone of a bluish colour, very hard, alternating with bands or beds of clayey sand, locally termed "Hassock," which is very fossiliferous . A lengthy list of fossils from these beds may be seen in the "Memoirs of the Geological Survey: On the Geology
SECTION OF UPPER NEOCOMIAN BEDS, FOLKESTONE.
H YTilE BBDS.
. .. ,.' ~
~ Clayey Beds. " ,'
Oalcar eouv Beet. .
F . G. H. PRI CE ON TH E LOW ER G R E E NS AND,
&c.
137
of F olkestone, &c.," published with Sheet IV. of the Survey Map s. Thi s deposit has a total thickness of 60 feet. I have not examined th ese beds lithologically, althou gh I have visited the qua rries several time s, and have made l\ considerable collection of fossils from t he variou s beds in that formation. I shall at pr esent r efrain from giving any list of t he fossils collected until I shall have had time to work out the beds systemat ically. The H ythe Beds ar e succeeded by th e Sandgate Beds of the Upper Neocomian, which come on between Hythe and Shorncliffe j they dip N.N.E., until th ey finally disappear beneath the sho re line a little eastward s of F olkest ono H arbour. The Sandgate Beds are the next in the series j th ey consist of dark sands and clayey sands supposed to attain a thickn ess of 80 feet. They: rest upon th e Hythe Beds of the same formation. I have lately had an opportunity of visiting these beds in company with Mr. Jukes Browne, of Cambridge, and John Griffiths, with whom I examined them carefully at F olkestone, east of the harbour, and above the turnpike on the Sandgate Road. Th e result of our exa mination was, that we came to the conclusion t hat this divi sion of th e Upp er Neocomian might be subdivided into four beds, to which I have affixed numb ers. No. I.-The base bed is composed of black sands, which are well seen at spring tid es on the shore a little eastward of F olkest one Harbour j at t he top of this bed many nodul es of iron pyrites occur, which frequently envelope specimens of Rhynchonella sulcata. Th e lower part of this bed I have not had an opportunity of exammmg , Thi s bed is appropriately called the "Zone of Rh y nchonella sulcata," as large numb ers are found in it. Thi s zone is very fossiliferous. The following is a list of the fossils obtained from it :Wood. Cones. Rhynchonella sulcata (Paek.). Asta~te ep, Crassatella Cornueliana (D'Orb.), Corbula sp, Cucullrea. glabra (Park.), Cytherea. sp, (ve~y abundant.),
Exogy~asinuata (Sow.). Gervillia anceps (Desh.), Myacites plicata (Sow.), Pectuneulus sp, Tellina..sp. Trigonia sp, Avellana inflata P (D'Orb.), Dentalium sp,
No.2. consists of dark green sand s, passing up into yellowishgreen sands. In the lower part of this bed, near Folkestone Harbour,
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F. G. H. PRICE ON THE LOWER GREENSAND
a few fossils have been observed, among which the following may be noted:Coral. Hemiaster sp,
Lima Cottaldina (D'Orb.) Ostrea frons (Park.)
No. 3.-Black clayey sand-s-in parts very much resembling Gault. No. 4.-The top bed of the series consists of yellowish-green sands, which are' gradually succeeded by brownish clayey sands. The Folkestone Beds of the Upper Neocomian form the high ground from above Hythe to Folkestone, where, gradually dipping N.N E., they are lost beneath tide mark at Copt Point. From Sandgate to Copt Point they form an'
Lucina sp, Trigonia sp, Avellana sp. J anira Morrisii, Ammonites, 2 sps,
This bed forms an excellent division between the Sandgate Beds and Folkestone Beds. The Second Division is composed of a dark greenish clayey sandstone, reminding one very much of the "Hassocky" beds in the Hythe section of the series. It is about 2ft. in thickness, and is fossiliferous, the following having been found : Serpula articulata (Sow). Rbyncbonella sp, Waldeimia pseudojurensis. Avicula pectiuata (Sow).
Ostrea frons (Park). n
sp,
Pecten orbicularis (Sow). Janira Morrisii.
The Third Division consists of about 60ft. of seams of coarse
139
AND GAULT OF FOLKESTONE.
calcareous sandstone, varying in thickness from 2ft. to a few inches, all of which are interstratified with layers of loose yellowish sand. It is from this bed that the stone is extracted for building which is generally known as Folkestone-stone, Large white tabular masses of branching sponge are met with upon these rocks. About 20ft. up in this bed the sand partakes of a black clayey character, but .this is not constant along the whole horizon, but occurs only in patches here and there. It is apparently fossiliferous, as I met with Pecten orbicularis and a species of .A8tarte in it. Within 10ft. of the top of this bed a seam of chert occurs. In the top seam of rock I observed, remarkably large quantities of Hemiaster; partly covered over with a mass of the branching sponge before cited. Specimens of the latter my friend Mr. -Iukes-Browneobtained with a view of submitting them for examination, to Mr. W. J. Sollas, of St. John's College, Cambridge, who, as is well known, has made a study of the sponges from the Upper Greensand of Cambridge, and I trust that within a short time the result of his investigation may be made known, In this bed the following fossils have been met with ; Polyzoa, Hemiaster sp. Spines of Micraster. Goniaster sp. Pseudodiadema, Serpula plexus (Sow.). Avicula peotinata (Bow.). Exogyra sinuata (Sow.).
Gervillie aneeps (Desh.). Janira ata.a (D'oeb.), Pecten orbicularis (Sow.), Perna sp, Avellsna sp, Waldheimia pseudo-jurensis. Ammonites sp.
The Fourth Division is the next and 'last bed I have to describe; it consists of an irregular seam of large rolled nodular masses of grit, composed of coarse grains of quartz, glauconite, jasper, lydian stone and phosphatic nodules. A considerable assemblage of fossils are obtained. from this bed, which is termed the Zone of Ammonites mammillaris. Its fossil contents are all more or less in the condition of rolled phospbatic casts, a list of which I give below. The seam is succeeded by about 4ft. of loose yellowish sands, which seldom yield any organic remains; this bed is capped by the line of nodules of sulphuret of iron which form the base of the Gault. I, roughly estimate the thickness of the whole formation at about 70ft. The following is a list of fossils from this division : L
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F. G. II. PRIOE ON THE LOWEn GREENSAND
Coral. 1I0laster sp, GoniaBter sp, Pseudodia.dema sp, Terehratul& mouteuiana, Exogyra conica (Sow.). .. sinnata (Sow.). Inoceramus coneentricua (Park.). .. Salomoni (D'Orb.), P ecten orbicularis (Sow.). Janira atava (D'Orb.), .. MorrisH. Area carinata (Sow.). Astarte sp, Cueulll1la ep, Lima Cottald ina (D'Orb.). Lueina sp, Cyprinasp.
Myacites plieata (Sow.). Nuenla peotinata(Sow.). Thetis loovigata P (Sow.). Trigonia Fittoni (Desh.), Pteroeeraa biearinatum (D'Orb.). Rostellaria sp, Ceritbium sp, Avellana sp, P (inflata P) P aludina ap,
Natiea Gaultina (D'Orb.) . .. Clementina (D'Orb.), Ammonites Bendantii (Brong.), mammillaria (Bcblotb.), sp . I'
lip.
Hamites rotundus Turrilites sp,
THE GAULT.
The Junction bed, Bed I, or bottom bed of th e Gault, first comes on, according to Mr. De Rance, in his paper on the Gault of Folkestone, at a point immediately over the turnpike on the Lower Sandgate Road, but I have failed to meet with it so far west on the coast section, but have examined this bed a little further inland at Cheriton, where some phosphatic diggings have been established. ThisJunction bed may be traced along the East Cliff until it also disappears below the beach, dipping N.N .E., a little eastward of Copt Point. The Gault must have been deposited in a subsiding area, and the sea of the time have been highly charged with sediment, caused by the denudation of the land, and by the action of the sea against the coast line. ' As all the fossils are so well preserved, they have doubtless been speedily covered by the sediment as it accumulated upon the floor of the Gault sea. When I say speedily, I would presume that the floor was composed of soft mud, and "that as the animals fell upon it, they were not suffered to roll about and become comminuted, but were gradually covered up by the sediment. Had it been otherwise, the fossils would not be so well preserved, but would appear as rolled casts similar to those in the nodule beds. r would suggest that these lines of nodules, mixed up as they are with rolled fossils, occurring so plentifully through the deposit, mark the floor of the sea during a period more or less
AND GAULT OF FOLKESTONE.
141
vast, when great physical changes may have turned the direction of the currents and so borne away the sediment, which would otherwise have been deposited, in another direction. In this way, these lines of nodules, which are larely more than one inch in thickness, may represent a period of time far greater than was required for the deposition of several feet of the clay. Thus, Bed VIII. with its several lines of nodules, would represent an enormously vast period, a period sufficiently long, as has been shewn, for over 100 species of Mollusca, forms plentiful in the Lower Gault, to become extinct. The Gault is composed of stiff clays and marls, more or less of a bluish grey colour, which are nowhere seen to such perfection as at Copt Point, and in East Weir Bay, about one mile eastward from Folkestone Harbour. It there has a thickness of about 100ft.; and from it a large number of fossils have been obtained in a very fine state of preservation. The Gault is divided into two divisions, the Upper and Lower, separated by a passage bed, and these are again sub-divided (as described in my paper "On the Gault of Folkestone," read before the Geological Society, on the 29th April last) into 11 well-marked zones, to which numbers have been attached for convenience, and provisional names assigned indicative of either the colour or fossil contents of the several bands. Before proceeding to describe the "arious beds, it may not be out of place in me to urge upon all geologists the necessity of collecting fossils systematically, that is to say, of carefully noting the horizons in which they occur, and to avoid collecting them indiscriminately, without any knowledge of their locality or position in the particular deposit from whence they may be derived; as by so doing, says my friend Mr. Bedwell, in his valuable paper "On Ammonite zones in the Upper Chalk of Margate" read before this Association last year, we destroy land-marks which might prove invaluable to others. Much more than as yet been accomplished might be done for Geology and Palreontology, were this course generally adopted. Many species, more especially species of Ammonites, are peculiar to .certain zones, constituting horizons; this, I may say without hesitation. has been fully proved. Thus by the knowledge of these zones, the geologist and palreontologist may ascertain and reckon the precise position of any fossil found. The measurements given by the various beds set forth Bub-
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F. G. H . PRICE ON THE LOW ER GREE NSAND
sequently in this paper, were t aken at Copt Point, and the "Pelter." I wish it to be understood that the divisions indicated in this paper are simply those of the Gault of Folkestone, th ey not having yet been proved to hold good over wide areas. It would be exceedingly difficult for anyone who had not thoroughly investigated the Gault in situ, to be able to make out the different beds, as they lie on the shore in East Weir Bay. In consequence of the water percolating through th e Chalk above meeting with the impervious floor of the Gault, a slide, as it were, is formed, and the Chalk slips over th e clayey beds into the sea. Thus, the Gault has been pres sed out and fault ed in great confusion, many of the beds being completely mixed tog ether. I took my measurements at Copt Point, commencing with the base of the Gault, or Junction-bed, Bed L, which rests upon the Folkestone Beds of the Upper Necomian, I shall therefore commence with that bed in. giving my description of the Gault. The lowest deposit is a line of nodul es of iron 'pyrites, succeeded by a band of dark greensand, containing two lines of phosphatic nodules, in which A mmonites interruptus occurs frequently, from which circumstance I propose to call this the Zone of A mnwnites interruptus. Many oth er fossils, mostly in th e form of rolled casts, occur in this bed j many of which are covered with small crystals of selenite, which is never noticed on fossils from any of the other beds. Upon many of the broken pieces of Ammonites interruptus the following forms have been met with in good preservation, indicating that they were contemporaneous with the formation of the deposit : Plicatula pectinoides Trochosmilia sulcata
Pecten quinqnecostatus Nucula sp,
The thickness of Bed 1, frOID the top of the Upper Neocomian, to the line of nodules and crushed band of fossils, is 10ft. lin. The next bed in ascending order is Bed II., which may, if we reckon the last as the Junction-bed, be considered the bottom of the Ganlt; it commences from the band of crushed fossils mixed with phosphatic nodules, and ends at a line where the clay becomes of a light fawn color, the thickness of which is 4ft. 2in. The clay of this bed is of a very dark colour, almost black, and is remarkable for the deep lustrous colour of its fossil contents,
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AND GAULT OF FOLKESTONE.
arising from the large quantities of iron pyrites contained in the bed. Three inches upwards from the base, there occurs a band of selenite, which is peculiar to this horizon. One foot higher a line of nodules is met with; between these two bands Aporrhais calcarata is found, and nowhere else. The lower part of this bed is the position of Nucula De Roncei, likewise peculiar to that horizon, seldom found in proximity with Aporrhais calcarata, Nine species appear to be peculiar to this bed, one which is a variety of Ammonites auritus possessed of long tubercles, in consequence of which I term this the Zone of Ammonites auritus var, Bed III, the "Light-bed," so called from the light colour of its clay-or "Crab-bed," from the quantity 'of crustaceans found in it-exhibits a striking contrast to the dark colour of the preceding. It is measured up to a line of nodules and rolled fossils, upon many of which the shell is preserved and carcpaces of crabs, Palceocorqstes Stokesii; and P. Broderipii, In thickness it does not exceed 4ft. Bin. It may be well to mention that tabular masses of clay ironstone are found in this bed at irregular intervals, a piece of which I submitted to my friend Mr. W. H. Huddleston, our Honorary Secretary who kindly analysed it for me, and found that it contained as much as 30 to 40 per cent. of metallic iron. Bed IV., is a very narrow band, being only 4in. in thickness; it is measured from the line of nodules before named, up to a line of phosphatic nodules and rolled casts of fossils. In these nodules a diminutive species of Hoploparia is found, which is never met with elsewhere. In colour the clay is somewhat darker than that of the preceding bed, and not mottled as is that of Bed V. Four species appear to be peculiar to the zone, these are : Natica obliqua, (described by me in my paper" On the Gault of Folkestone," read before the Geological Society); Fusus Gaultinus, an ammonite with very long spines, which may be considered a variety of Ammonites tuberculatus, and Ammonites De La Ruei, a form belonging to the Cristati group. I may here remark that from my experience I have noticed that the lower division is characterized by the presence of the Dentati and Tuberculati group of Ammonites, which are deeply grooved, whereas the upper division is remarkable for the presence of the (lristati group of Ammonites, thus, the meeting with Am. De La Ruei in this bed, and Am. Roissyanus in Bed No.1, both belonging to the Cristati group, form the exceptions to the rule, the only exception in the Upper
or
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F. G. H. PRICE ON THE LOWER GREENSAND
Gault being a variety of Ammonites lautus, This bed may be called the" Zone of Ammonites De La Ruei." Bed V.-This is called the "Coral bed, " from the quantity of those beautiful little fossils it contains. The clay is of a dark colour, spotted to within a few inches of the top with light fawncoloured markings. The bed is only Ift, 6in. in thickness, being measured from the line of nodules containing rolled casts of fossils, up to a line where the clay becomes more strongly marked. Eight species are peculiar to this horizon, which I have named the " Zone of Ammonites lautus:" Bed VI., called the "Mottle-bed," from the lightish-coloured markings which throughout pervade the clays of this bed, is of small vertical thickness, probably not more than one foot. It is measured from the top of the preceding zone to a hard seam. The clay is darker in colour than that of Bed V. It may be considered the "Zone of the Ammonites denarius." There are six species that I have met with peculiar to it, which are:Homolopsis Edwardsii (Bell) Necrocarcinus Bechei (Deslong.) FUBuselegans (D'Orb.) Sealarie gastyna (D'Orb.)
Turrilites Hugardianus (D'Orb.) and a small variety of Ammonites cornutus (Pictet)
Bed VII. usually styled the "Dark-bed," is the top of the Lower Gault, and is measured from the hard seam forming the limit of Bed VI., up to the first line of nodules in Bed VIII. It has a thickness of 6ft. 2in., and the clays are of a very dark colour, though not so dark as those of Bed II. It is highly fossiliferous, as many as 64 species have been obtained from it. The class Gasteropoda appears to have reached its maximum of development in this zone. There are several species peculiar to it. Ammonites auritus occurs in large quantities, from which circumstance I propose to call it the "Zone of Ammonites auritus." Buccinum Gaultinum first appears in the middle of this bed, and is continued into the Nodule-bed as above. The following are only found in this bed:Nucula albensis (D'Orb.) Aporrbais Parkinsoni (Sow.)
FU8us Indeclsus (D'Orb.) Cerithium tectum (D'Orb.)
Bed VIII., usually called the "Nodule bed" from the large number of phosphatic nodules it contains, is measured from the first line of nodules forming the top of Bed VII. to a second line of nodules, and has a thickness of lOin. This bed is a true junction
AND GAULT OF FOLKESTONE.
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or passage bed, dividing the Upper from the Lower Gault. It holds many species belonging to both divisions, and marks the total extinction of many of the Lower Gault forms, no less than the introduction of others which took their place. In my note on the last bed, Bed VII., I mentioned the fact of its being peculiarly fruitful in Gasteropoda, Now it may be worth recording that few species of this Class pass into Bed VIII. at all, those which do being generally in the form of rolled casts much encrusted with phosphate. Out of 47 species obtained from the Lower division only 10 of them pass into this passage-bed; it likewise contains three species peculiar to it. In the Upper Gault 11 species of Gasteropoda have been met with, six of which are continued from the Lower division, the remaining five being peculiar to the Upper. This appears to point to the fact that the conditions which obtained during the deposition of the Upper Gault were unfavourable to the continuance of the more delicate forms of life, or, if on the other hand they were continued, that the chemical constituents of the sediments deposited during the process of the formation of these marls were unfavourable to the preservation of specimens. During the period I have paid attention to this formation, I have collected as many as 247 speciesof all Classes from the Gault of Folkestone, that I have been able to assign to particular genera; but there are fully 25 other forms that have been met with, which up to the present time I have been unable to determine. Out of the above number 124 forms become extinct in Bed VIII.; and 46 forms are continued into the Upper Gault. In addition to this bed containing the limit fauna, it possesses 20 species peculiar to itself. As many as 57 new forms, none of which have been observed in the Lower Gault, make their first appearance in Bed VIII., or in a higher zone, thus constituting the number of the fauna hitherto observed as being peculiar to the Upper beds. Ammonites belonging to the various groups are of frequent occurrence in this bed; the most characteristic species is Ammonites cristatus, from which circumstance I propose to name this bed the" Zone of Ammonites cristatus." Among the Ammonites peculiar to this zone the following may be mentioned as occurring : Ammonites Beudantii (Brong.) " Brongniartianm (Pictet.) It Iterianus (D'Orb.)
Ammonites Selliguinus (Brong.) "
splendenaf-a grooved varlet,-
"
tuberculatus, a variety.
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F. G. H. PRICE O~ THE LOWER GREENSAND
Cucullaa glabra (Park.), Cyprina quadrata (D'Orb.), and Scalaria Gaultina (D'Orb.), are especially characteristic of the bed. Bed IX. forms the base of the Upper Gault; the geologist will at all times be able to indicate his position by the large quantities of crushed forms of Inoceramu s sulcatus contained in this bed. It is true that this well-marked form occurs in the Zone of Amm onites cristatus, but in no great numbers. It is mentioned by Mr. De Rance, in his valuable paper" On the Albian, or Gault of Folkestone," that this shell first occurs in the Lower Neocomian clay of Hythe j is not again found in the Aptian seri es, but reappears in the Zone of Am7ll'lnites interruptus ; a single specimen only, however, has been found by Mr. Etheridge. Had that specimen been recorded as being met with in that zone by anyone else than our distinguished Vice-President, I should have doubted the circumstance, as I have repeatedly found this fossil at Copt Point, mingled with the fragments of Ammonites interruptus, but have always considered it to have been knocked out of the Upper Gault, and rolled into this place probably by the action of the waves. I should much like to prove the matter by finding one myself in situ. This bed is measured from the line of n'odules at the top of the last described up to a line of nodules,containing vast quantities of crushed forms of Inoceramus sulcatus. The thickness of this bed inches. Inoc eramus sulcatus, first met with in the is 9 feet Zone of Ammonites cristatus, does not pass out of Bed IX. The Gault of this zone is full of them j one can hardly dig up a foot of the marly clay withont seeing the shining casts of dozens of them. In this same bed is found an intermediate form between this and Ino cel'amus concentl'icus. This fossil was named Inoceramus sub8ulcatus by the Rev. T. Wiltshire, Griffiths, the well-known collector of Gault fossils at Folkestone, styles this zone the" half and half bed," in consequence of the frequency of occurrence of this hybrid form. Almost as numerous as Inoceramus sulcatus is the Ammonites. oaricosus, which first appears in Bed VIII., and is sometimes met with in Bed X.; but it attains its maximum of development in the bed now under consideration, in consequence of which I have called this the "Zone of Ammonites varicosus." A variety of the well known Ammonites lautu8 occurs in this zone, forming another exception to the rule of the Upper Gault being restricted to the Cristati group, It ranges from the Nodulebed, Bed VIIL, up to a. hard seam near the top of the Zone of
4t
AND GAULT OF FOLKESTONE.
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Ammonites varicosus, above which it has never been observed. This is the only exception known to me of an Ammonite of the Dentati group being met with in the Upper Gault. Below this hard seam, Ammonites rostratus (Sow.), the Ammonites inflatus of D'Orbigny, makes its first appearance, and extends up to the base of the Upper Greensand. From this bed specimens of Pinites hexagonus (Carruthers) have been obtained. In the discussion which followed my paper read before the Geological Society, Mr. Carruthers referred to the discovery by Mr. Gardner and myself of cones of two species of Sequoia, "and, associated with these, some species of Pinus, two of which were to be referred to a group of that genus at present found associated with two existing species of Sequoia on the mountains of western North America. These sequoise from the Gault are the oldest known representatives of the genus; and it is remarkable that they should be thus early associated with species of the same group of pines which is now represented only in the same country where the sequoire also grow." It may be worth remarking that Pholadomya fabrina (D'Orb.) is only met with in situ in this bed; it, however, appears in Bed VIII. in the form of rolled casts. Bed X. commences at the crushed band of Inoceramus eulcatus and extends to a line of phosphatic nodules, containing specimens of Pecten Raulinianu8 (D'Orb.), which line occurs at 5 feet 1 inch above the limit of the last zone. The Gault of this bed partakes more of the character of marl than of the preceding beds; it is hard, and of a cold, pale grey colour, and poor in organic remains, which fact may possibly be due to the large percentage of carbonate of lime the Upper Gault has been proved to contain; to which cause we may certainly ascribe the disappearance of the lustrous shells from the fossils. A line of phosphatic nodules occurs at 2 feet 8 inches above Bed IX., containing large quantities of Plicatula pectinoides, which are there met with in fair condition. Between these two lines of phosphatic nodules, giving a space of 2 feet 5 inches, the Gault is mottled, and masses of Pentacrinus Fittoni occur. This is remarkable, as in all other parts of the deposit it is only met with in pieces. Cidaris Gaultina is likewise peculiar to this circumscribed position, These lines of nodules produce many fragments of chelonian and fish bones, likewise teeth of Hybodu8 and Otodus appendiculatus. The most remarkable forms ever obtained from this bed are
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F. G. H. PRICE ON THE LOWER GREENSAND
some circular and more or less compressed bodies, possessing the texture of egg shells. To the best of my belief only three of these fossils have ever been discovered, two of which are in the cabinet of Mr. J. S.-Gardner, F.G.S., and one in my own collection. This latter I showed to Mr. J. W. Hulke, F.G.S., who considered it as probably quite new, and that in the coarse pitting of the shell it resembled that of Crocodilus biporeatus (?). The most characteristic fossil in this bed is Kingama lima (Defrance). From the frequency of its recurrence, my friend Mr. De Rance named this zone after it, in his paper "On the Albian, or Gault of Folkestone," and I readily adopt the same conclusion arrived at by him, and propose that this bed should be styled the Zone of Kingena lima. The following fossils are peculiar to this zone : Goniaster sp. Kingena lima (Defrance) Hinnites sp,
Astarte sp, Aporrhais maxima (Price) Orocodilus biporeatus (P)
Bed XI. -This bed, equal to more than half of the whole formation in thickness, consists of a cold, pale grey marl, traversed }}y a series of dark partings, the smooth portions between which are smeared over with a coating of oxide of iron. My friend Mr. W. H. Hudleston, F.G.S., was kind enough to analyse a piece of gault from this bed, and found that it was a marl, with particles in a minute state of subdivision, the bulk of the mass being a mixture of chalk and clay, containing a few extremely small quartz grains, and after treatment with acid one or two translucent greenish grains were observed; ~lso fragments of pyrites and small crystals. This sample, which was dried at 100 c., was found to contain 26'45 of carbonate of lime, being nearly 18 per cent. more than is contained in Bed II. This bed yields 2.55 per cent. of metallic iron. In the upper portion of the bed, at a distance of 85 feet 6 inches from the base of it, a seam of dark green sand obtains, having a thickness of 3 feet 3 inches. This is called by Griffiths the "Middle Greensand." The marly clay above this green sand is for the first few feet much intermixed with green grains, after which it assumes the same homogeneous marly character as the lower portion of the bed. There is 17 feet 6 inches of Gault above the green sand seam. Immediately below this seam a small form of Ptychoceras occurs,
AND GAULT OF FOLKESTONE.
149
always in iron pyrites, which is not met with in any other part of the deposit. I have also found the Hylospongia of SolIas there. Several lines of nodules occur in the band of green sand, chiefly composed of pyriform sponges. The following Fossils are likewise met with : Trochocyathus eonulus (Edw. & H.) Pollieipes sp, Avicnl.. grypbreoides (Sow.) Pecten orbicularis (Sow.) Plieatnla pectinoides (Sow.) " sigillum (Sow.)
Aporrhais Orbignyana (Pictel et Raux) Solarium ornatum (Sow.) Ammonites Goodballii (Sow.) Belemnites ultimus (D'Orb.) Drepanephorus canaliculatus (Eg .) Icthyosaurus campylodon (Carter)
Immediately above this seam Ammonites variana, a form so characteristic of the Chalk Marl, is first met with. Inoceramus Crispii, and Ammonites rostratus, attain very large dimensions in this bed, the latter being frequently met with measuring over 12 inches in diameter. This zone may be termed the" Zone of Ammonites rostratus, Before concluding this paper, it may be of value to name the following forms as being characteristic of the whole formation, they having continued in every zone throughont the period occupied by the deposition of these clays : Plicatula pectinoides (Sow.) Inoceramus concentricus (Park.) Nucula ovata (Mantell.) " pectinata (Sow.)
Aporrhais Orbignyana (Pictet et Raux). Natica Gaultina (D'Orb.) Dentalinm decussatum (Sow.) Nautilus clementinus (D'Orb.)
The class Brachiopoda has been found to be confined to Upper Gault entirely, Terebratula biplicata first appearing in a rolled form in the Zone of Ammonites cristatus, and continuing upwards through the several beds; it is, however, most abundant in the Zones of Ammonites oaricosus and Kingena lima. It ever apPEtars to me to be remarkable that Rhynchonella has not been met with in the Gault, and I cannot directly ascertain where any. specimens of that genus have been met with in the Folkestone Beds of the Upper Neocomian. Only one species appears to have been described from the Red Chalk of Hunstanton, and that is the Rhynchonella sulcata (Park.), which occurs in large quantities in the Sandgate Beds of the Upper Neooomian, near Folkestone Harbour, both embedded in the sands and in masses agglutinated together with iron pyrites, this particular zone being No. 1., before cited. Now no species of this genus is met with in this area from this zone upwards till we reach the Chalk Marl,
150
F. G. H. PRICE ON THE LOWER GREENSAND, &C.
where it again obtains, missing alike the Gault and Upper Greensand. It would be interesting to ascertain what were the conditions at that period prevalent in these seas which caused this interesting genus to migrate to some outer area.
2.
ON A COLLECTION OF FOSSILS FROM THE UPPER GREENSAND OF MORDEN, CAMBRIDGESHIRE.
By H.
GEORGE FORDHAM,
ESQ.,
F.G.S.
This collection is from the so-called "Coprolite" or phosphatic nodule beds of the Upper Greensand or Chloritic Marl, at two localities neal' Ashwell and Morden, on the borders of Hertfordshire and Cambridgeshire, where pits for the extraction of the nodules have been worked for some years. Mr. Bonney, in a paper read before this Association two years ago,· has so clearly detailed the general configuration of the country, the position of the bed and mode of working for the nodules, near Cambridge, and his description applies so well to this part of the country, that it is not necessary for me to touch on these points. The bed is from 18 inches to 3! feet in thickness, and varies considerably in the proportion of nodules. It graduates into the Chalk Marl above j the glauconitic grains extending higher than the nodules, and the nodules being more abundant in the lower part of the bed. The origin and cause of formation of phosphatic deposits at the period of the Gault and Greenssnds is one which is of great interest to the geologist, and is one of the important geological problems which have yet to be solved. The great number oflocalities in Europe at which phosphatic deposits of this period have been found would incline one to believe that the sea at that time was more highly charged, in the European area at least, with phosphate of lime than it is at present. I am inclined to think that the more probable solution of this question is to account for the excess by the presence of the remains of fish and other animals in larger quantities than now exist in our seas. The occurrence of certain pebbles and boulders of foreign rocks, sometimes rounded by attrition, has been ascribed by Messrs. W. J. Sollas and A. J. Jukes-Brown in an interesting paper, (Quart. • .. Proceedings of the Geologists' Association," vol. rii., p. 1.
185
The following were elected Members of the Association : Baron de la Taille des Essarts; Esq. j and John T. Young, Esq.
Francis Robert Morrison,
The following Papers were read : -
1.
ON THE LOWER GREENSAKD AND GAULT OF FOLKESTONE.
By
F. G.
H.
PRICE, ESQ., F.G.S., F.R.G.S,
M.A.I.
It is my intention this evening to lay before you a sbort account of' the Upper Neocomian and Gault of' Folkestone, than which place I mllY remark, for the benefit of those who happen to be unacquainted with the district, there is..no better locality on the south-east coast of England for the student of Cretaceous geology. If he makes that interesting old town his head quarters, he can take some most valuable and instructive rambles into the surrounding district, where fine and extended sections of all the various stages of the Cretaceous beds, from the Wealden, west of Hythe, to the Upper Chalk, near Dover, can be found. THE LOWER GREENSAKD.
The town of Folkestonc is situated upon the Folkestone Beds of the Upp er Neoeomian, In order to find the base of the Upper Neocomian series, we must go to Aldington Knowl, situated about five miles westward of Hythe, where the Atherfleld Clay forms a long inland cliff extending to Hythe, but, as we are informed by Mr. Drew, F.G.S., in the" Memoirs of the Geological Survey," the beds of the Kentish Rag have slipped down and covered it up, consequently it is seldom seen. It is about 30 feet in thickness, and may be seen at very low water on the shore ncar Shornc1iffe Battery. The Hythe Beds likewise make their first appearance at Aldington Know1; the lower ground to the south being occupied by the W cald Clays j very fine sections of the Hythe Beds or Kentish Rag may be seen in the quarries at the back of the town of Hythe, from whence the Rag-stone is extracted largely for building. It is a Iimestone of a bluish colour, very hard, alternating with bands or beds of clayey sand, locally termed "Hassock," which is very fossiliferous . A lengthy list of fossils from these beds may be seen in the "Memoirs of the Geological Survey: On the Geology
SECTION OF UPPER NEOCOMIAN BEDS, FOLKESTONE.
H YTilE BBDS.
. .. ,.' ~
~ Clayey Beds. " ,'
Oalcar eouv Beet. .
F . G. H. PRI CE ON TH E LOW ER G R E E NS AND,
&c.
137
of F olkestone, &c.," published with Sheet IV. of the Survey Map s. Thi s deposit has a total thickness of 60 feet. I have not examined th ese beds lithologically, althou gh I have visited the qua rries several time s, and have made l\ considerable collection of fossils from t he variou s beds in that formation. I shall at pr esent r efrain from giving any list of t he fossils collected until I shall have had time to work out the beds systemat ically. The H ythe Beds ar e succeeded by th e Sandgate Beds of the Upper Neocomian, which come on between Hythe and Shorncliffe j they dip N.N.E., until th ey finally disappear beneath the sho re line a little eastward s of F olkest ono H arbour. The Sandgate Beds are the next in the series j th ey consist of dark sands and clayey sands supposed to attain a thickn ess of 80 feet. They: rest upon th e Hythe Beds of the same formation. I have lately had an opportunity of visiting these beds in company with Mr. Jukes Browne, of Cambridge, and John Griffiths, with whom I examined them carefully at F olkestone, east of the harbour, and above the turnpike on the Sandgate Road. Th e result of our exa mination was, that we came to the conclusion t hat this divi sion of th e Upp er Neocomian might be subdivided into four beds, to which I have affixed numb ers. No. I.-The base bed is composed of black sands, which are well seen at spring tid es on the shore a little eastward of F olkest one Harbour j at t he top of this bed many nodul es of iron pyrites occur, which frequently envelope specimens of Rhynchonella sulcata. Th e lower part of this bed I have not had an opportunity of exammmg , Thi s bed is appropriately called the "Zone of Rh y nchonella sulcata," as large numb ers are found in it. Thi s zone is very fossiliferous. The following is a list of the fossils obtained from it :Wood. Cones. Rhynchonella sulcata (Paek.). Asta~te ep, Crassatella Cornueliana (D'Orb.), Corbula sp, Cucullrea. glabra (Park.), Cytherea. sp, (ve~y abundant.),
Exogy~asinuata (Sow.). Gervillia anceps (Desh.), Myacites plicata (Sow.), Pectuneulus sp, Tellina..sp. Trigonia sp, Avellana inflata P (D'Orb.), Dentalium sp,
No.2. consists of dark green sand s, passing up into yellowishgreen sands. In the lower part of this bed, near Folkestone Harbour,
138
F. G. H. PRICE ON THE LOWER GREENSAND
a few fossils have been observed, among which the following may be noted:Coral. Hemiaster sp,
Lima Cottaldina (D'Orb.) Ostrea frons (Park.)
No. 3.-Black clayey sand-s-in parts very much resembling Gault. No. 4.-The top bed of the series consists of yellowish-green sands, which are' gradually succeeded by brownish clayey sands. The Folkestone Beds of the Upper Neocomian form the high ground from above Hythe to Folkestone, where, gradually dipping N.N E., they are lost beneath tide mark at Copt Point. From Sandgate to Copt Point they form an'
Lucina sp, Trigonia sp, Avellana sp. J anira Morrisii, Ammonites, 2 sps,
This bed forms an excellent division between the Sandgate Beds and Folkestone Beds. The Second Division is composed of a dark greenish clayey sandstone, reminding one very much of the "Hassocky" beds in the Hythe section of the series. It is about 2ft. in thickness, and is fossiliferous, the following having been found : Serpula articulata (Sow). Rbyncbonella sp, Waldeimia pseudojurensis. Avicula pectiuata (Sow).
Ostrea frons (Park). n
sp,
Pecten orbicularis (Sow). Janira Morrisii.
The Third Division consists of about 60ft. of seams of coarse
139
AND GAULT OF FOLKESTONE.
calcareous sandstone, varying in thickness from 2ft. to a few inches, all of which are interstratified with layers of loose yellowish sand. It is from this bed that the stone is extracted for building which is generally known as Folkestone-stone, Large white tabular masses of branching sponge are met with upon these rocks. About 20ft. up in this bed the sand partakes of a black clayey character, but .this is not constant along the whole horizon, but occurs only in patches here and there. It is apparently fossiliferous, as I met with Pecten orbicularis and a species of .A8tarte in it. Within 10ft. of the top of this bed a seam of chert occurs. In the top seam of rock I observed, remarkably large quantities of Hemiaster; partly covered over with a mass of the branching sponge before cited. Specimens of the latter my friend Mr. -Iukes-Browneobtained with a view of submitting them for examination, to Mr. W. J. Sollas, of St. John's College, Cambridge, who, as is well known, has made a study of the sponges from the Upper Greensand of Cambridge, and I trust that within a short time the result of his investigation may be made known, In this bed the following fossils have been met with ; Polyzoa, Hemiaster sp. Spines of Micraster. Goniaster sp. Pseudodiadema, Serpula plexus (Sow.). Avicula peotinata (Bow.). Exogyra sinuata (Sow.).
Gervillie aneeps (Desh.). Janira ata.a (D'oeb.), Pecten orbicularis (Sow.), Perna sp, Avellsna sp, Waldheimia pseudo-jurensis. Ammonites sp.
The Fourth Division is the next and 'last bed I have to describe; it consists of an irregular seam of large rolled nodular masses of grit, composed of coarse grains of quartz, glauconite, jasper, lydian stone and phosphatic nodules. A considerable assemblage of fossils are obtained. from this bed, which is termed the Zone of Ammonites mammillaris. Its fossil contents are all more or less in the condition of rolled phospbatic casts, a list of which I give below. The seam is succeeded by about 4ft. of loose yellowish sands, which seldom yield any organic remains; this bed is capped by the line of nodules of sulphuret of iron which form the base of the Gault. I, roughly estimate the thickness of the whole formation at about 70ft. The following is a list of fossils from this division : L
140
F. G. II. PRIOE ON THE LOWEn GREENSAND
Coral. 1I0laster sp, GoniaBter sp, Pseudodia.dema sp, Terehratul& mouteuiana, Exogyra conica (Sow.). .. sinnata (Sow.). Inoceramus coneentricua (Park.). .. Salomoni (D'Orb.), P ecten orbicularis (Sow.). Janira atava (D'Orb.), .. MorrisH. Area carinata (Sow.). Astarte sp, Cueulll1la ep, Lima Cottald ina (D'Orb.). Lueina sp, Cyprinasp.
Myacites plieata (Sow.). Nuenla peotinata(Sow.). Thetis loovigata P (Sow.). Trigonia Fittoni (Desh.), Pteroeeraa biearinatum (D'Orb.). Rostellaria sp, Ceritbium sp, Avellana sp, P (inflata P) P aludina ap,
Natiea Gaultina (D'Orb.) . .. Clementina (D'Orb.), Ammonites Bendantii (Brong.), mammillaria (Bcblotb.), sp . I'
lip.
Hamites rotundus Turrilites sp,
THE GAULT.
The Junction bed, Bed I, or bottom bed of th e Gault, first comes on, according to Mr. De Rance, in his paper on the Gault of Folkestone, at a point immediately over the turnpike on the Lower Sandgate Road, but I have failed to meet with it so far west on the coast section, but have examined this bed a little further inland at Cheriton, where some phosphatic diggings have been established. ThisJunction bed may be traced along the East Cliff until it also disappears below the beach, dipping N.N .E., a little eastward of Copt Point. The Gault must have been deposited in a subsiding area, and the sea of the time have been highly charged with sediment, caused by the denudation of the land, and by the action of the sea against the coast line. ' As all the fossils are so well preserved, they have doubtless been speedily covered by the sediment as it accumulated upon the floor of the Gault sea. When I say speedily, I would presume that the floor was composed of soft mud, and "that as the animals fell upon it, they were not suffered to roll about and become comminuted, but were gradually covered up by the sediment. Had it been otherwise, the fossils would not be so well preserved, but would appear as rolled casts similar to those in the nodule beds. r would suggest that these lines of nodules, mixed up as they are with rolled fossils, occurring so plentifully through the deposit, mark the floor of the sea during a period more or less
AND GAULT OF FOLKESTONE.
141
vast, when great physical changes may have turned the direction of the currents and so borne away the sediment, which would otherwise have been deposited, in another direction. In this way, these lines of nodules, which are larely more than one inch in thickness, may represent a period of time far greater than was required for the deposition of several feet of the clay. Thus, Bed VIII. with its several lines of nodules, would represent an enormously vast period, a period sufficiently long, as has been shewn, for over 100 species of Mollusca, forms plentiful in the Lower Gault, to become extinct. The Gault is composed of stiff clays and marls, more or less of a bluish grey colour, which are nowhere seen to such perfection as at Copt Point, and in East Weir Bay, about one mile eastward from Folkestone Harbour. It there has a thickness of about 100ft.; and from it a large number of fossils have been obtained in a very fine state of preservation. The Gault is divided into two divisions, the Upper and Lower, separated by a passage bed, and these are again sub-divided (as described in my paper "On the Gault of Folkestone," read before the Geological Society, on the 29th April last) into 11 well-marked zones, to which numbers have been attached for convenience, and provisional names assigned indicative of either the colour or fossil contents of the several bands. Before proceeding to describe the "arious beds, it may not be out of place in me to urge upon all geologists the necessity of collecting fossils systematically, that is to say, of carefully noting the horizons in which they occur, and to avoid collecting them indiscriminately, without any knowledge of their locality or position in the particular deposit from whence they may be derived; as by so doing, says my friend Mr. Bedwell, in his valuable paper "On Ammonite zones in the Upper Chalk of Margate" read before this Association last year, we destroy land-marks which might prove invaluable to others. Much more than as yet been accomplished might be done for Geology and Palreontology, were this course generally adopted. Many species, more especially species of Ammonites, are peculiar to .certain zones, constituting horizons; this, I may say without hesitation. has been fully proved. Thus by the knowledge of these zones, the geologist and palreontologist may ascertain and reckon the precise position of any fossil found. The measurements given by the various beds set forth Bub-
142
F. G. H . PRICE ON THE LOW ER GREE NSAND
sequently in this paper, were t aken at Copt Point, and the "Pelter." I wish it to be understood that the divisions indicated in this paper are simply those of the Gault of Folkestone, th ey not having yet been proved to hold good over wide areas. It would be exceedingly difficult for anyone who had not thoroughly investigated the Gault in situ, to be able to make out the different beds, as they lie on the shore in East Weir Bay. In consequence of the water percolating through th e Chalk above meeting with the impervious floor of the Gault, a slide, as it were, is formed, and the Chalk slips over th e clayey beds into the sea. Thus, the Gault has been pres sed out and fault ed in great confusion, many of the beds being completely mixed tog ether. I took my measurements at Copt Point, commencing with the base of the Gault, or Junction-bed, Bed L, which rests upon the Folkestone Beds of the Upper Necomian, I shall therefore commence with that bed in. giving my description of the Gault. The lowest deposit is a line of nodul es of iron 'pyrites, succeeded by a band of dark greensand, containing two lines of phosphatic nodules, in which A mmonites interruptus occurs frequently, from which circumstance I propose to call this the Zone of A mnwnites interruptus. Many oth er fossils, mostly in th e form of rolled casts, occur in this bed j many of which are covered with small crystals of selenite, which is never noticed on fossils from any of the other beds. Upon many of the broken pieces of Ammonites interruptus the following forms have been met with in good preservation, indicating that they were contemporaneous with the formation of the deposit : Plicatula pectinoides Trochosmilia sulcata
Pecten quinqnecostatus Nucula sp,
The thickness of Bed 1, frOID the top of the Upper Neocomian, to the line of nodules and crushed band of fossils, is 10ft. lin. The next bed in ascending order is Bed II., which may, if we reckon the last as the Junction-bed, be considered the bottom of the Ganlt; it commences from the band of crushed fossils mixed with phosphatic nodules, and ends at a line where the clay becomes of a light fawn color, the thickness of which is 4ft. 2in. The clay of this bed is of a very dark colour, almost black, and is remarkable for the deep lustrous colour of its fossil contents,
143
AND GAULT OF FOLKESTONE.
arising from the large quantities of iron pyrites contained in the bed. Three inches upwards from the base, there occurs a band of selenite, which is peculiar to this horizon. One foot higher a line of nodules is met with; between these two bands Aporrhais calcarata is found, and nowhere else. The lower part of this bed is the position of Nucula De Roncei, likewise peculiar to that horizon, seldom found in proximity with Aporrhais calcarata, Nine species appear to be peculiar to this bed, one which is a variety of Ammonites auritus possessed of long tubercles, in consequence of which I term this the Zone of Ammonites auritus var, Bed III, the "Light-bed," so called from the light colour of its clay-or "Crab-bed," from the quantity 'of crustaceans found in it-exhibits a striking contrast to the dark colour of the preceding. It is measured up to a line of nodules and rolled fossils, upon many of which the shell is preserved and carcpaces of crabs, Palceocorqstes Stokesii; and P. Broderipii, In thickness it does not exceed 4ft. Bin. It may be well to mention that tabular masses of clay ironstone are found in this bed at irregular intervals, a piece of which I submitted to my friend Mr. W. H. Huddleston, our Honorary Secretary who kindly analysed it for me, and found that it contained as much as 30 to 40 per cent. of metallic iron. Bed IV., is a very narrow band, being only 4in. in thickness; it is measured from the line of nodules before named, up to a line of phosphatic nodules and rolled casts of fossils. In these nodules a diminutive species of Hoploparia is found, which is never met with elsewhere. In colour the clay is somewhat darker than that of the preceding bed, and not mottled as is that of Bed V. Four species appear to be peculiar to the zone, these are : Natica obliqua, (described by me in my paper" On the Gault of Folkestone," read before the Geological Society); Fusus Gaultinus, an ammonite with very long spines, which may be considered a variety of Ammonites tuberculatus, and Ammonites De La Ruei, a form belonging to the Cristati group. I may here remark that from my experience I have noticed that the lower division is characterized by the presence of the Dentati and Tuberculati group of Ammonites, which are deeply grooved, whereas the upper division is remarkable for the presence of the (lristati group of Ammonites, thus, the meeting with Am. De La Ruei in this bed, and Am. Roissyanus in Bed No.1, both belonging to the Cristati group, form the exceptions to the rule, the only exception in the Upper
or
144
F. G. H. PRICE ON THE LOWER GREENSAND
Gault being a variety of Ammonites lautus, This bed may be called the" Zone of Ammonites De La Ruei." Bed V.-This is called the "Coral bed, " from the quantity of those beautiful little fossils it contains. The clay is of a dark colour, spotted to within a few inches of the top with light fawncoloured markings. The bed is only Ift, 6in. in thickness, being measured from the line of nodules containing rolled casts of fossils, up to a line where the clay becomes more strongly marked. Eight species are peculiar to this horizon, which I have named the " Zone of Ammonites lautus:" Bed VI., called the "Mottle-bed," from the lightish-coloured markings which throughout pervade the clays of this bed, is of small vertical thickness, probably not more than one foot. It is measured from the top of the preceding zone to a hard seam. The clay is darker in colour than that of Bed V. It may be considered the "Zone of the Ammonites denarius." There are six species that I have met with peculiar to it, which are:Homolopsis Edwardsii (Bell) Necrocarcinus Bechei (Deslong.) FUBuselegans (D'Orb.) Sealarie gastyna (D'Orb.)
Turrilites Hugardianus (D'Orb.) and a small variety of Ammonites cornutus (Pictet)
Bed VII. usually styled the "Dark-bed," is the top of the Lower Gault, and is measured from the hard seam forming the limit of Bed VI., up to the first line of nodules in Bed VIII. It has a thickness of 6ft. 2in., and the clays are of a very dark colour, though not so dark as those of Bed II. It is highly fossiliferous, as many as 64 species have been obtained from it. The class Gasteropoda appears to have reached its maximum of development in this zone. There are several species peculiar to it. Ammonites auritus occurs in large quantities, from which circumstance I propose to call it the "Zone of Ammonites auritus." Buccinum Gaultinum first appears in the middle of this bed, and is continued into the Nodule-bed as above. The following are only found in this bed:Nucula albensis (D'Orb.) Aporrbais Parkinsoni (Sow.)
FU8us Indeclsus (D'Orb.) Cerithium tectum (D'Orb.)
Bed VIII., usually called the "Nodule bed" from the large number of phosphatic nodules it contains, is measured from the first line of nodules forming the top of Bed VII. to a second line of nodules, and has a thickness of lOin. This bed is a true junction
AND GAULT OF FOLKESTONE.
145
or passage bed, dividing the Upper from the Lower Gault. It holds many species belonging to both divisions, and marks the total extinction of many of the Lower Gault forms, no less than the introduction of others which took their place. In my note on the last bed, Bed VII., I mentioned the fact of its being peculiarly fruitful in Gasteropoda, Now it may be worth recording that few species of this Class pass into Bed VIII. at all, those which do being generally in the form of rolled casts much encrusted with phosphate. Out of 47 species obtained from the Lower division only 10 of them pass into this passage-bed; it likewise contains three species peculiar to it. In the Upper Gault 11 species of Gasteropoda have been met with, six of which are continued from the Lower division, the remaining five being peculiar to the Upper. This appears to point to the fact that the conditions which obtained during the deposition of the Upper Gault were unfavourable to the continuance of the more delicate forms of life, or, if on the other hand they were continued, that the chemical constituents of the sediments deposited during the process of the formation of these marls were unfavourable to the preservation of specimens. During the period I have paid attention to this formation, I have collected as many as 247 speciesof all Classes from the Gault of Folkestone, that I have been able to assign to particular genera; but there are fully 25 other forms that have been met with, which up to the present time I have been unable to determine. Out of the above number 124 forms become extinct in Bed VIII.; and 46 forms are continued into the Upper Gault. In addition to this bed containing the limit fauna, it possesses 20 species peculiar to itself. As many as 57 new forms, none of which have been observed in the Lower Gault, make their first appearance in Bed VIII., or in a higher zone, thus constituting the number of the fauna hitherto observed as being peculiar to the Upper beds. Ammonites belonging to the various groups are of frequent occurrence in this bed; the most characteristic species is Ammonites cristatus, from which circumstance I propose to name this bed the" Zone of Ammonites cristatus." Among the Ammonites peculiar to this zone the following may be mentioned as occurring : Ammonites Beudantii (Brong.) " Brongniartianm (Pictet.) It Iterianus (D'Orb.)
Ammonites Selliguinus (Brong.) "
splendenaf-a grooved varlet,-
"
tuberculatus, a variety.
146
F. G. H. PRICE O~ THE LOWER GREENSAND
Cucullaa glabra (Park.), Cyprina quadrata (D'Orb.), and Scalaria Gaultina (D'Orb.), are especially characteristic of the bed. Bed IX. forms the base of the Upper Gault; the geologist will at all times be able to indicate his position by the large quantities of crushed forms of Inoceramu s sulcatus contained in this bed. It is true that this well-marked form occurs in the Zone of Amm onites cristatus, but in no great numbers. It is mentioned by Mr. De Rance, in his valuable paper" On the Albian, or Gault of Folkestone," that this shell first occurs in the Lower Neocomian clay of Hythe j is not again found in the Aptian seri es, but reappears in the Zone of Am7ll'lnites interruptus ; a single specimen only, however, has been found by Mr. Etheridge. Had that specimen been recorded as being met with in that zone by anyone else than our distinguished Vice-President, I should have doubted the circumstance, as I have repeatedly found this fossil at Copt Point, mingled with the fragments of Ammonites interruptus, but have always considered it to have been knocked out of the Upper Gault, and rolled into this place probably by the action of the waves. I should much like to prove the matter by finding one myself in situ. This bed is measured from the line of n'odules at the top of the last described up to a line of nodules,containing vast quantities of crushed forms of Inoceramus sulcatus. The thickness of this bed inches. Inoc eramus sulcatus, first met with in the is 9 feet Zone of Ammonites cristatus, does not pass out of Bed IX. The Gault of this zone is full of them j one can hardly dig up a foot of the marly clay withont seeing the shining casts of dozens of them. In this same bed is found an intermediate form between this and Ino cel'amus concentl'icus. This fossil was named Inoceramus sub8ulcatus by the Rev. T. Wiltshire, Griffiths, the well-known collector of Gault fossils at Folkestone, styles this zone the" half and half bed," in consequence of the frequency of occurrence of this hybrid form. Almost as numerous as Inoceramus sulcatus is the Ammonites. oaricosus, which first appears in Bed VIII., and is sometimes met with in Bed X.; but it attains its maximum of development in the bed now under consideration, in consequence of which I have called this the "Zone of Ammonites varicosus." A variety of the well known Ammonites lautu8 occurs in this zone, forming another exception to the rule of the Upper Gault being restricted to the Cristati group, It ranges from the Nodulebed, Bed VIIL, up to a. hard seam near the top of the Zone of
4t
AND GAULT OF FOLKESTONE.
147
Ammonites varicosus, above which it has never been observed. This is the only exception known to me of an Ammonite of the Dentati group being met with in the Upper Gault. Below this hard seam, Ammonites rostratus (Sow.), the Ammonites inflatus of D'Orbigny, makes its first appearance, and extends up to the base of the Upper Greensand. From this bed specimens of Pinites hexagonus (Carruthers) have been obtained. In the discussion which followed my paper read before the Geological Society, Mr. Carruthers referred to the discovery by Mr. Gardner and myself of cones of two species of Sequoia, "and, associated with these, some species of Pinus, two of which were to be referred to a group of that genus at present found associated with two existing species of Sequoia on the mountains of western North America. These sequoise from the Gault are the oldest known representatives of the genus; and it is remarkable that they should be thus early associated with species of the same group of pines which is now represented only in the same country where the sequoire also grow." It may be worth remarking that Pholadomya fabrina (D'Orb.) is only met with in situ in this bed; it, however, appears in Bed VIII. in the form of rolled casts. Bed X. commences at the crushed band of Inoceramus eulcatus and extends to a line of phosphatic nodules, containing specimens of Pecten Raulinianu8 (D'Orb.), which line occurs at 5 feet 1 inch above the limit of the last zone. The Gault of this bed partakes more of the character of marl than of the preceding beds; it is hard, and of a cold, pale grey colour, and poor in organic remains, which fact may possibly be due to the large percentage of carbonate of lime the Upper Gault has been proved to contain; to which cause we may certainly ascribe the disappearance of the lustrous shells from the fossils. A line of phosphatic nodules occurs at 2 feet 8 inches above Bed IX., containing large quantities of Plicatula pectinoides, which are there met with in fair condition. Between these two lines of phosphatic nodules, giving a space of 2 feet 5 inches, the Gault is mottled, and masses of Pentacrinus Fittoni occur. This is remarkable, as in all other parts of the deposit it is only met with in pieces. Cidaris Gaultina is likewise peculiar to this circumscribed position, These lines of nodules produce many fragments of chelonian and fish bones, likewise teeth of Hybodu8 and Otodus appendiculatus. The most remarkable forms ever obtained from this bed are
148
F. G. H. PRICE ON THE LOWER GREENSAND
some circular and more or less compressed bodies, possessing the texture of egg shells. To the best of my belief only three of these fossils have ever been discovered, two of which are in the cabinet of Mr. J. S.-Gardner, F.G.S., and one in my own collection. This latter I showed to Mr. J. W. Hulke, F.G.S., who considered it as probably quite new, and that in the coarse pitting of the shell it resembled that of Crocodilus biporeatus (?). The most characteristic fossil in this bed is Kingama lima (Defrance). From the frequency of its recurrence, my friend Mr. De Rance named this zone after it, in his paper "On the Albian, or Gault of Folkestone," and I readily adopt the same conclusion arrived at by him, and propose that this bed should be styled the Zone of Kingena lima. The following fossils are peculiar to this zone : Goniaster sp. Kingena lima (Defrance) Hinnites sp,
Astarte sp, Aporrhais maxima (Price) Orocodilus biporeatus (P)
Bed XI. -This bed, equal to more than half of the whole formation in thickness, consists of a cold, pale grey marl, traversed }}y a series of dark partings, the smooth portions between which are smeared over with a coating of oxide of iron. My friend Mr. W. H. Hudleston, F.G.S., was kind enough to analyse a piece of gault from this bed, and found that it was a marl, with particles in a minute state of subdivision, the bulk of the mass being a mixture of chalk and clay, containing a few extremely small quartz grains, and after treatment with acid one or two translucent greenish grains were observed; ~lso fragments of pyrites and small crystals. This sample, which was dried at 100 c., was found to contain 26'45 of carbonate of lime, being nearly 18 per cent. more than is contained in Bed II. This bed yields 2.55 per cent. of metallic iron. In the upper portion of the bed, at a distance of 85 feet 6 inches from the base of it, a seam of dark green sand obtains, having a thickness of 3 feet 3 inches. This is called by Griffiths the "Middle Greensand." The marly clay above this green sand is for the first few feet much intermixed with green grains, after which it assumes the same homogeneous marly character as the lower portion of the bed. There is 17 feet 6 inches of Gault above the green sand seam. Immediately below this seam a small form of Ptychoceras occurs,
AND GAULT OF FOLKESTONE.
149
always in iron pyrites, which is not met with in any other part of the deposit. I have also found the Hylospongia of SolIas there. Several lines of nodules occur in the band of green sand, chiefly composed of pyriform sponges. The following Fossils are likewise met with : Trochocyathus eonulus (Edw. & H.) Pollieipes sp, Avicnl.. grypbreoides (Sow.) Pecten orbicularis (Sow.) Plieatnla pectinoides (Sow.) " sigillum (Sow.)
Aporrhais Orbignyana (Pictel et Raux) Solarium ornatum (Sow.) Ammonites Goodballii (Sow.) Belemnites ultimus (D'Orb.) Drepanephorus canaliculatus (Eg .) Icthyosaurus campylodon (Carter)
Immediately above this seam Ammonites variana, a form so characteristic of the Chalk Marl, is first met with. Inoceramus Crispii, and Ammonites rostratus, attain very large dimensions in this bed, the latter being frequently met with measuring over 12 inches in diameter. This zone may be termed the" Zone of Ammonites rostratus, Before concluding this paper, it may be of value to name the following forms as being characteristic of the whole formation, they having continued in every zone throughont the period occupied by the deposition of these clays : Plicatula pectinoides (Sow.) Inoceramus concentricus (Park.) Nucula ovata (Mantell.) " pectinata (Sow.)
Aporrhais Orbignyana (Pictet et Raux). Natica Gaultina (D'Orb.) Dentalinm decussatum (Sow.) Nautilus clementinus (D'Orb.)
The class Brachiopoda has been found to be confined to Upper Gault entirely, Terebratula biplicata first appearing in a rolled form in the Zone of Ammonites cristatus, and continuing upwards through the several beds; it is, however, most abundant in the Zones of Ammonites oaricosus and Kingena lima. It ever apPEtars to me to be remarkable that Rhynchonella has not been met with in the Gault, and I cannot directly ascertain where any. specimens of that genus have been met with in the Folkestone Beds of the Upper Neocomian. Only one species appears to have been described from the Red Chalk of Hunstanton, and that is the Rhynchonella sulcata (Park.), which occurs in large quantities in the Sandgate Beds of the Upper Neooomian, near Folkestone Harbour, both embedded in the sands and in masses agglutinated together with iron pyrites, this particular zone being No. 1., before cited. Now no species of this genus is met with in this area from this zone upwards till we reach the Chalk Marl,
150
F. G. H. PRICE ON THE LOWER GREENSAND, &C.
where it again obtains, missing alike the Gault and Upper Greensand. It would be interesting to ascertain what were the conditions at that period prevalent in these seas which caused this interesting genus to migrate to some outer area.
2.
ON A COLLECTION OF FOSSILS FROM THE UPPER GREENSAND OF MORDEN, CAMBRIDGESHIRE.
By H.
GEORGE FORDHAM,
ESQ.,
F.G.S.
This collection is from the so-called "Coprolite" or phosphatic nodule beds of the Upper Greensand or Chloritic Marl, at two localities neal' Ashwell and Morden, on the borders of Hertfordshire and Cambridgeshire, where pits for the extraction of the nodules have been worked for some years. Mr. Bonney, in a paper read before this Association two years ago,· has so clearly detailed the general configuration of the country, the position of the bed and mode of working for the nodules, near Cambridge, and his description applies so well to this part of the country, that it is not necessary for me to touch on these points. The bed is from 18 inches to 3! feet in thickness, and varies considerably in the proportion of nodules. It graduates into the Chalk Marl above j the glauconitic grains extending higher than the nodules, and the nodules being more abundant in the lower part of the bed. The origin and cause of formation of phosphatic deposits at the period of the Gault and Greenssnds is one which is of great interest to the geologist, and is one of the important geological problems which have yet to be solved. The great number oflocalities in Europe at which phosphatic deposits of this period have been found would incline one to believe that the sea at that time was more highly charged, in the European area at least, with phosphate of lime than it is at present. I am inclined to think that the more probable solution of this question is to account for the excess by the presence of the remains of fish and other animals in larger quantities than now exist in our seas. The occurrence of certain pebbles and boulders of foreign rocks, sometimes rounded by attrition, has been ascribed by Messrs. W. J. Sollas and A. J. Jukes-Brown in an interesting paper, (Quart. • .. Proceedings of the Geologists' Association," vol. rii., p. 1.