Excursion to Cambridge and Barrington

268

EXCURSION TO CAMBRIDGE AND BARRINGTON.

A vote of thanks to the Directors was passed, and the members left by train for London at 7.43 p.m. REFERENCES. 1884.

NEHRING, A.-Fosslle P/erde aus deutschen Diluvial-Ablagerungen. (Berlin: Paul Parey). 1892 • PRESTWICH, J.-" The • Head' or • Rubble-Drift' of the South of England." Quart. Journ. Geol. Soc., vol. xlviii, 1893. IRVING, A.-" On Post-Eocene Surface Changes in the London Basin." Geoi. ,Vag., dec. iii, vol. x, p. 21I. 18 96. SALTER, A. E.-" Pebbly Gravel from the Goring Gap to the Norfolk Coast," Proc. Geol, Assoc., vol. xiv, p. 389. 18 97. IRVING, A.-" Excursion to Bishop's Stortford." Proc. Geol. Assoc., vol. xv, p. 193. 1898• - - - - - " The Geology of the Stort Valley." Ibid., p. 224. Geol. Mag., dec. v, J9 04· HOLST, N. '0.-" The Inter-glacial Question." vol. i, p. 433. IRVING, A.-" High Level Plateau-gravels." Geot. Mag.• dec. v, vol. i, p. 497. See also Rtp. Brit. Assoc. Cambridge, p. 572. - - - - - " Excursion to Bishop's Stortford and Stansted." Proc, Geol. Assoc., vol. xix, p. 222. EWART, J. C._" The Derivation of the Modern Horse." Quarter(1' Review. April, No. 41I. 1909. WINDLE, B. C. A.-" Remains of the Prehistoric Age in England." Mtthuen & Co. 19 10 • BONNEY, T. G.-Presidential Address, Rep. Brit. Assoc., Sheffield,p. 3. 1910• IRVING, A.-" A Buried Valley through the Mercian Chalk Range, etc." Op. cit., p. 6 In . ._ - - " The Bishop's Stortford Prehistoric Horse." Op. cit., 19 10 • P·73 6. *** The Shilling Guides to the Stone Age and the Bronze Age of the British Museum also very useful.

EXCURSION TO

CAMBRIDGE AND BARRINGTON,

SATURDAY, JUNE 17TH,

IgIl.

Director: PROF. T. McKENNY HUGHES, M.A., F.R.S., F.G.S. Excursion Secretary: A. C. YOUNG. (Report bJ' THE DIRECTOR.)

A PARTY of thirty-five met at Cambridge Station at 12.20 and motored, via Haslingfield, to Barrington, where they were met by Prof. and Mrs. McKenny Hughes. The village of Barrington lies about seven miles south-west of Cambridge. It may be reached by several different routes. The train runs along the eastern edge of the river-gravels past Trumpington to Shelford, where it crosses the Granta, and then skirts the base of the Chalk

EXCURSION TO CAMBR ID GE AND BARRINGTON.

26 9

hills to Foxton Station. The best road is that through Trumpington, Hauxton, and Harston to Fo xton Station, where we have to cross the lin e twice by an awkward and unnecessary turn. Another route is by Haslingfield, over a very ste ep hill, to Barrington Church. . . . A glance at th e on e inch Geological Map (Drift) will show th at by th e first two rout~s w~ pass over an extensiv.e plain con sisting of Chalk Marl with river-gravels almost continuous from Cambridge to Shelford, and int.errupted patches of the .same froJ? Haslingfield to ab out half a mile west of Foxton Station, Th~s gravel is of the type of the Barnwell Grav:I, an~ has been, and is being, dug in many places, and exposed In railway cutungs . It

SSE

/ F IG . 23 .- S ECTI ON T HRO UGH THE BARRiNGTON PITS, NEA R CAMBRIDGE. -

T. McK. Hughes. b. Boulder Clay. c. Barrington Beds (marl, loam, sand and gravel). d. Chalk. I. Zone of Rh. cuuieri j 2. Melbourne Rock j 3. Cherryhinton Chal k (= zone of Hola ster subg/obosus) ; 4. Burwell R ock. e, Chalk Marl , with phospha te bed (= Cambridge Greensand) at base.

.f. Gault.

The relat ive th ickn esses of the beds are not observed in this diag ram .

is at a much lower level than th e Barrington Bed s, and contains a different group of fossils. On reaching Foxton Station we turn sharply to the righ t and follow a zigzag road to the east en d of Barringto n village . Gravel was once extens ively work ed alon g th is road and yielde d remains of th e mam mo th, etc. Beyond th is mass to th e west th ere is no more gravel seen, and along the road from She pret h Station to the pits at th e west end of Barrington we pass Mr. Gildea's cement works, where the Chalk Marl is seen at th e surface with no bed of gravel restin g upon it, though pans and pipes indicate its form er extension over this area. To return to th e zigzag road above mentioned, about a mile from Foxton Sta tion we cross one of the branches of th e Cam, here called th e R hee, which was embanked and held up in Norman times, close to the edge of th e rising ground on the north, to serve the anci ent mill, now known as Quaker's Mill .

270

EX CUR SION T O CAMB R IDGE AN D BARRI NGT ON.

A stee p bit of road between Quaker's Mill and the Vicarage carries us up about 20 feet on to the terrac e on which stands the village of Barrington, which we enter at its east end, and we cross th e village green in ab out a mile. Near the west end a small tributary valley cuts through the Barrington terrace and causes some complications in the superficial deposits higher up. A similar steep rise at the end of the stra ight road from Shepr eth Station carri es us on to th e west end of the Barrington terrace. Here are the pits in which th e sections now described occur, on ground belonging to Mr. Ca rda, who has most kindly given permission to Professor Hughes to carr yon resear ches in them.

a

c

e

25:::;& f . . e:::;

FIG. 24.-SECTIO N AT B AR RIN GTO N, NEAR C AMBRIDG E.-

T. MeX. H ughes.

a. Made ground, with old surface soil at base. c. Barri ngton Beds.

e Chal k Marl. /. Gault.

Fig. 23 is a diagram to illustrate the relation of th e beds tra versed. The lower level gravel rests on the Chalk Marl for some distance north and west of Foxton Station, but between Shepreth Station and the Barr ington terrace the Chalk Marl is seen at the surfac e. The Barr ington Bed s (c) form part of this terrace, but the Chalk Marl is at the surface over the greater part of this higher area also, as may be seen in the most northerly of the pits. There is no marked feature to indicate where the Barrington Beds come on, while the difficulty of tracing any of the surface beds over the area where the Chalk Marl occurs at a small distance below the surface is greatly increased by so much of th e ground having been dug over for phosphate nodules. In some of the parts where the Marl runs deeper and has not been disturbed, as in most of th e pits, the Chalk Marl, with the Phosphate

EXCURSION TO CAMBRIDGE AND BARRINGTON.

27 I

Bed (Cambridge Greensand) at the base, is seen resting on the Gault as shown in the sections. The terrace ends somewhat abruptly on the west, but on the east continues, with interruptions due to denudation by small transverse streams, through the village, and seems to die out gradually beyond the Vicarage towards Harston. It is important to observe what deposits are available as a source from which the material of the Barrington Beds might be derived. The hill on the north is chiefly in the zone of Holaster subglobosus, the Burwell Rock making no conspicuous feature at its base. On the top, above the horizon of the Melbourne Rock, some of the zone of RhYlldwnella tuvieri remains. The whole hilltop is capped with a heavy mass of lead-coloured Boulder Clay (b). (See Fig. 23.) In the May number of the Geological Magazine (I9II), p. 229, the Rev. Osmond Fisher called attention to the 'glaciated pebbles of hard chalk which occur in the lower part of this clay, and describes the manner in which the clunch itself, beneath the clay, shows signs, in sheared and slickensided surfaces, of having been dragged along. At a distance of about a mile from the rise of the Chalk on the north the Barrington Beds run across the spur which the terrace here forms. Its pebbly basement-bed may be seen in one of the pits abutting against a slope of Chalk Marl (see Fig. 24), but making little or no feature on the surface. A hundred yards or so farther to the north there is a deep pit in the Chalk Marl with only traces of the once overlying superficial deposits which have been removed from this part of the terrace. In the section Fig. 25 (a) the surface soil and the top earth, thrown aside when the pits were first opened, are seen above the Barrington Beds (c), which are a mass of marl, loam, sand, and gravel here about r a ft, in depth. These lie on the lower beds of the Chalk Marl (d) with the phosphate bed at the base resting upon the Gault (e). Plate XL, Fig. I (from a photograph by Mrs. Hughes) shows the appearance of the section as seen by the Association on June 17th. The four figures are standing in front of the excavations in which the bones were exposed; under their feet is the material thrown out; their heads are opposite the old surface soil, and the mounds of white marl above that level were thrown up when the pit was first opened for brick-making, etc. The dog is swimming in the pit in about 20 ft. of water. The upper part of the deposit, where first exposed, consisted almost entirely of resorted Chalk, so that when the Geological Survey Map was constructed this bed was not distinguished from the true Chalk Marl. When, later on, extensive excavations were made for the

27 2

EXCURSION TO CAMBRIDGE AND BARRINGTON.

purpose of procuring marl for cement, gault for bricks, and the phosphatic nodules at the base of the Chalk for the manufacture of superphosphate, we fortunately had as Vicar of Barrington the Rev. Edward Cony beare, «0 and as Vicar of HarIton, about I ~ mile farther north, the Rev. Osmond Fisher, t and by them the records of one of the most interesting districts in East Anglia, both geologically and archreologically, have been preserved. In discussing the age and origin of the Barrington Beds, the first point to be considered is its relation to the physical features of the district. We notice, as we approach Barrington from Cambridge, that near Harston the hills on either hand close on

a ..-

(

'

..

...:.

~

...

-'"

--

........

- ..

c ...,"4 _ __ . . ~

FIG. 25.-SECTION AT BARRINGTON, NEAR CAMBRIDGE.-

T. MeK. Hughes.

(For description of Beds, see page 271.)

the valley, and we pass through a narrow opening into a wide undulating but low country, part of the north margin of which is skirted by the Barrington terrace. The Barrington Beds do not coincide in extent with this terrace, but near the village terminate at a considerable distance from the foot of the hills. This makes it almost impossible that the pebbly gravel at the base of the Barrington Beds can have been washed down from the high ground on the north. Again, a small uplift or barrier of any kind across the existing valley near Harston would dam up the water to the level of the Barrington terrace, or even cause it to flow out in the other direction into the Ivel. As from the fauna we infer that the deposit is of freshwater origin, we may speculate as to whether it is due to a temporary lake or to an • Hist, of Cambs., Lond., Elliot Stock, 1897. t Quart. ]OU11I. Geol. Soc., vol. xxxv (1870), p. 670; Geol. Mag., May (19"), p. 229.

EXCURSION TO CAMBRIDGE AND BARRINGTON.

273

embayed turn in a river of no great velocity, probably winding about over flat ground. The character of the material also is peculiar. The upper part for 5 or 6 ft. consists of resorted chalk; in this there are very few stones, bones, or shells, but such as do occur favour the view that the whole forms one series. About half-way down in the sections now exposed (see Fig. 25), lines and lenticular beds of angular flint gravel occur, and occasionally sand in small beds or disseminated throughout the mass, or replacing the pebble-bed at the base. This basementbed is a very remarkable deposit of gravel I or 2 ft. in thickness, consisting chiefly of pebbles or subangular pieces of white quartz, quartzite, and hard chalk, like Chalk Rock, with occasional bits of jasper and igneous or metamorphic rock. There are also angular and subangular flints, from the condition and colour of their surface evidently derived from older gravels and surface soils, and some chipped and faceted pieces of black flint, such as are now found in similar association on the shore of Norfolk. It is difficult to explain how the large stones were transported. They and the bones seem to have been thrown together very irregularly over the surface of the Chalk Marl. The large piece of sandstone shown in PI. XL, Fig. 2, and Plate XLI, Fig. I, from photographs by Mr. Krusin, between the jaw of Elephas antiquus and that of Rhinoceros leptorhinus, is jammed into the bone perhaps by the pressure of the mass when the bone had begun to decay. There are several large masses of this basement-bed hardened and preserved in the Sedgwick Museum which will enable anyone to study its mode of occurrence. One very significant fact must be noted. Many of the bones seem to have been broken and the fragments drifted together, but in other cases a large portion of the skeleton has been transported into the deposit before the ligaments had perished, as in the case of the vertebral column of a hippopotamus shown in Plate XLI, Fig. 2. The most remarkable thing about the deposit is that it is not made up of the winnowings of the Boulder Clay which lies deep along the tops of the adjoining hills. In that the boulders are largely derived from Jurassic Rocks, but these are absent from the Barrington Gravel. We must infer from this either that the Barrington deposit is older than the Boulder Clay, or that the direction of the denuding forces did not allow the material to be drawn from that source, a difficult supposition to maintain. The stones in the Barrington Beds have not acquired their form and surface condition from the waters in which they were last laid down. Some are rolled pebbles, some quite sharply angular. The large pebbles of hard chalk can hardly have come from the bed at the base of the Boulder Clay described by Mr. Fisher, as

274

EXCURSION TO CAMBRIDGE AND BARRINGTON.

we must then have had Jurassic and other stones from the same source. These pebbles of hard chalk are of very wide occurrence. They occur at the base of the gravel at Redhills, near Cambridge; but there we find plenty of other material from the Boulder Clay. There must have been various older deposits, now all gone, which furnished the stones in the Barrington basement-bed. Excepting the chalk boulders, they very closely resemble the stones of the pebbly gravel of the Highest Plain, which lies under the Boulder Clay of Hertfordshire. '*' It is true that we have in the Barrington Beds, as in the gravels of the Upper Plain of Hertfordshire, fragments and boulders which cannot have been derived from any rocks at the surface in the existing drainage area, but in all our speculations as to the origin, age, and mode of transport of boulders in East Anglia, we have to bear in mind that we have at any rate two pre-Glacial sources of supply: (I) the Basement Bed of the Chalk (the Cambridge Greensand) which crops out over a large part of the closely adjoining area, and (2) the Lower Greensand, in which I have found a trilobite in a fragment of Carboniferous chert, besides a great variety of basic and acidic igneous rocks. These may have been derived from the ancient subterranean plateau, which has now been touched in so many places in East Anglia at a depth of 1,000 ft., more or less. The soft sand is blown or washed away by the gentler sub-aerial agents of denudation, and the boulders remain on the surface, a source of error in collecting glacial boulders. I have never admitted into our collection of boulders from the Cambridge Greensand any specimens that had not the sealmark given by its characteristic Plicatula sigillina. If next we consider the palreontological evidence we meet with difficulties, but the balance of evidence is in favour of warm and probably pre-glacial conditions. The following mollusca have been found in the Barrington Beds by Mrs. Hughes. The specimens are of small size and mostly young, and the number of species is very small as compared with those recorded from Barnwell and Grantchester. We note especially the absence of Cyrena jluminalis and Unio litoralis. There was a peaty bed in a hollow in the Barrington Beds, formerly exposed in a pit a short distance to the north-east, in which a large number of freshwater shells occurred, but the relation of this bed to the Barrington Beds was not clear, and specimens found there may have been recorded in previous lists as from the pits at Barrington. Mrs. Hughes wishes to acknowledge the kind help which she has always received from Mr. Hugh Watson in the determination of the specimens.

* Quart. ]outn.

Geol, Soc., vo!. xxiv (1868), p. 283.

P ROC. GEOL.

Assoc.,

VOL.

XXII.

PLATE

XL

FIG. I.-P IT AT B AR RI NGT ON, NEAR CA~IIl RIDGE.

.~

1/,. A I

I,

F IG. 2 .-BISON, E LEPH ANT, A:-ln RHI NOCE ROS I~ THE BA R RI NGTON BE DS. To fa ce pag e .2i...

EXCURSION TO CAMBRIDGE AND BARRINGTON.

Eucanulus fulvus (Muller). Helicella virgata (Da C.).* H. itala (Linne)." Mostly young: some specimens of instabilis (Ziegler). Hygromia hispida (Linne). H. sericea, Drap. [ liberta (Westerlund)], * also a conical variety. Vallonia pulchtlla (Muller).* V. excentrica (Sterki).* V. costata (MUller). * Helix nemoraiis (Linne).Cochlicopa lttbrica (Fer.). * Jaminia muscorum (Linne),* also var. brevis (Baud.). Vertigo antivertigo (Drap.), *

=

275

Sucdnea putris (Linne). S. elegans (Risso).* S. oblO?tga (Drap.).* S. schumacherii (Andr).* Limnaa pereger (MUller).* L. palustris (Muller).L. truncatula (Muller).* Bithynia tentaculata (Linne)." Planorbis spirorois (Linne)." P. ieucostoma (Mill.).* Valvata piscinaiis (Muller). V. cristata (Muller). Pomatias elegans (Muller). Sph(J!rium corneum? (Linne) Pisidium amnicum (M Liller), *' and three other species.

Mr. Kennard pointed out the occurrence of several species. which had not previously been recognised from this locality,. amongst them that of Sucanea schumacherii, and added the following, which have been so far found here by him only: Agriolimax agrestis, Arion sp., Punctum pygm(J!um, Vertigo pygmtea. Those recorded by Mr. Kennard, as well as by Mrs. Hughes, are marked by an asterisk in the list, and we may hope that after further visits from him more hitherto unrecognised species may be found itt situ or detected in the material already collected. With regard to the form Sucanea schumacherii, he allows Mrs. Hughes to append the following extract from a letter kindly written by him to her on the subject. After referring to specimens from Barrington, from Hale Moss, Westmorland, and from the Pleistocene deposits of Osterode, Germany, he says, "It was originally described as a var. of S. oblonga by Dr. Andreoe, but Dr. W ust has raised it to the rank of a species, and I think he is right. It is a characteristic German Pleistocene fossil. The original description is in • Der Diluvial Sand von Hangerbeiten,' Abhand. d. Geoi. Spec. Karte von Elsass Lbthringen, Band iv, Heft ii, pp. 68-9, Ihf.2, Fig. 96-100." The history of this species is interesting in its bearing upon the probable conditions of the district when the Barrington Beds were deposited. It seems to be able to adapt itself to change, living in what is a swamp in winter and an arid plain in summer. The facies of the shells from the Barrington Loam and Gravel is, as far as it goes, almost identical with that of the Cambridge district to-day. But in the far more numerous shells of Barnwell and Grantchester there are at least seven foreign and locally extinct shells, some of which now range into warmer regions. PROC. GEOL. Assoc., VOL. XXII, PART 5, 19II.] 22

276

EXCURSION TO CAMBRIDGE AND BARRINGTON.

The following is a list of the mammalian remains in the Sedgwick Museum obtained from the Barrington Beds: Bison priscus, Bojan. Hyama crocuta (= H. spekea, Goldf). Bas (primigenius) urus, Ceesar, Cervus megaceros, Hart. Rhinoceros leptorhinus. C. elaphus, Linn. Ursus priscus (= U. spelceus, C. dama; var, clactonianus, Falc, Blum). Elephas antiquus, Falc. Meles taxus, Owen. Equus caballus, Meyer. Canis vulpes. Felis leo (=speltea), Goldf. Teeth of mice. Hippopotamus amphibius, L. ( =.H. major, Cuv.). We have found several limb and other bones of a small deer in the Barrington Beds. This Mr. C. E. Gray has always been inclined to refer to Cervus dama, and there seems to be good authority in support of this view. Though the Ceruus dama of our parks was probably carried into Britain in Roman times from its natural habitat in the warmer countries of the Mediterranean region, its precursor, differing slightly from our modern Fallow deer, may very likely have migrated here at the same time that Barrington was inhabited by such an obviously Southern group as that which we see in the above list. Falconer, from an examination of some antlers found at Clacton, assigned them to a distinct species, Certrus clactonianus, and Dawkins has given two names, C. brown; and C.falconeri, to similar forms. We have not found the antlers, and it will be sufficient for our present purpose to indicate this Barrington deer as C. dama var, clacto1lianus? It will be noticed that Elephas prim;genius and Rhinoceros tichorhinus are absent, and that they are represented by E. antiquus and Rh. leptorhinus. Meles taxus and Canis vulpes, being burrowing animals, may have got in later. The whole group seems to favour the idea that the climate was warmer than that which suited the hairy elephant and woolly rhinoceros. The hyrena has left the marks of his teeth upon many of the bones, and small fragments which have apparently been gnawed by large carnivores are common, but in addition to this the rounded ends and edges of some of the thick limb bones suggest weathering or rolling in water. Figs. 26 and 27 show two of the most common and characteristic fossils of the deposit. Fig. 26 is Rhinoceros leplorhinus or hemit«chus, showing well the stage with half partition in the nose. The upper molars are reflected in the mirror below. Fig. 27 is that of the most perfect skull we have obtained of Hippopotamus amphibius.

EXCURSION TO CAMBRIDGE AND BARRINGTON.

277

FIG. 26.*-RHINOCEROS LEPTORHINUS OR HEMIT
These notes must be regarded only as a collection of facts submitted for examination, firstly to the Excursion of June, 1911,

FIG. 27.*-HIPPOPOTAMUS AMPHIBIUS, FROM BARRINGTON • • Figs. 26 and 27 are reproduced by permission of the Cambridge University Press.

278

EXCURSION TO BUSHEY, OXHEY, AND WATFORD HEATH.

and now inviting further criticism from the more numerousreaders of the PROCEEDINGS. NOTE BY THE EXCURSION SECRETARY,

A. C.

YOUNG.

At 4 p.m, the members motored back to Cambridge via Foxton and Trumpington, At Clare College they were sumptuously entertained by Prof. and Mrs. Hughes in the College Hall, after which a very hearty vote of thanks was accorded to our hosts. At 6 p.m. members proceeded to the Sedgwick Museum, where the Director and his assistants, especially Mr. R. H. Rastall, conducted them over the various galleries, lecture rooms, students' working rooms, libraries, etc., and the Director discoursed in his peculiarly interesting way on some of the more interesting specimens and those which had special reference to the Barrington gravels visited during the afternoon. At 7.3° the members strolled about the" backs" of the Colleges and other places of interest, and returned to London by the 8.45 train.

EXCURSION TO BUSHEY, OX HEY, WATFORD HEATH. SATURDAY, JUNE 24TH,

AND

1911.

Directors: H. KIDNER, F.G.S., AND J. H. WOODHEAD, F.G.S. Excursion Secretary: G. J. ROBERTS. (Report by

MR. KIDNER.)

A PARTY of 22 were met at Bushey by the Directors about 3 p.m. The Hertfordshire Natural History Society took part in the excursion. The party was conducted southwards through the Bushey Cutting. Mr. Woodhead explained that by the platform at Bushey Station there had been found a mass of Chalk 3 or 4 ft. higher than the general level of the Chalk surface, and at the top of the Chalk there were a number of large nodular flints. Immediately south of the platform, near the signal box, the" bottom bed" of Reading pebbles occurs; and Mr. Woodhead said that from the signal box all the way to the first bridge, and a few yards beyond, the rail way line is on the "bottom bed" of pebbles, excepting two or three places where higher beds have been let down by dissolution of the Chalk. Irnrnediatelv south of the signal box, the" bottom bed" had been seen to "a thickness of 7 ft. The top of the bed was about 4 or 5 ft. above the level of the rails, and its total thickness here apparently cannot be more than 8 to 10 ft. The writer described