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Easter Field Meeting, 1933. Tenby and the South Pembrokeshire Coast
391 EASTER FIELD MEETING, 1933. TENBY AND THE SOUTH PEMBROKESHIRE COAST. REPORT
BY
THE DIRECTORS; THE PRESIDENT AND E. E. L. DIXON, B.Sc., F.G.S. [Received lsi November, 1933.]
THE party assembled at Tenby on the evening of Thursday, April rjth, headquarters being, as on the occasion of the former visit in 1909, at the Cobourg Hotel. About forty members attended and these, with a few friends and local visitors, made a total of nearly fifty who attended during some or all of the series of excursions. Miss G. M. Bauer acted as Secretary for the Meeting. Friday, April 14th.
Freshwater East, Swanlake and Manorbier. Leaving Tenby at 9.15 a.m., the party drove along the Ridgeway to the highest point (about 350 ft. O.D.) where, beside Norchard Beacon barrow, the Directors drew attention to the landscape features and their relation to the 'solid' geology of the district. Continuing thence to Lamphey the party crossed the Pembroke syncline to Freshwater East, where the relation of the valley which here opens to the sea to the denuded Freshwater East anticline was indicated. No exposures of the Ordovician shales, which outcrop in the valley, could be examined, but fossiliferous horizons were accessible in the Silurian (Wenlock Beds-poorly seen and without distinctive fossils-and Ludlow Beds) below the basement-conglomerates of the Old Red Sandstone (Downtonian) in the southern cliffs of the bay. The party studied the outcrops of the Ludlow Beds and Downtonian (A uchenaspis Group) also in the cliffs on the northern side of the bay, and here Prof. W. H. Lang gave an account of his work on the fossil plants in the local Old Red Sandstone. A fine cephalaspid fish which he had found in the A uchenaspis Group and generously presented to Jermyn Street Museum-the most complete specimen of an Old Red fish known from Pembrokeshire, as some of the body-segments were preserved-was identified by Sir Arthur Smith Woodward as a Hemicyclaspis of the Murchisoni group. The beautiful cliffs that extend from Freshwater East to Old Castle Head display the vertical beds in the northern limb of the Freshwater East anticline. Coastal profiles include the elements of (1) plateau, (2) scarp bevelled off along the cleavage with an almost uniform southerly slope of about 30 degrees, (3) shore-platform of recent marine erosion, (4)sea-cliff at the head of this platform. On this occasion, when bright sunlight brought
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out all the varied colours of the rocks, the scenery of the cliffs was admirably displayed. The party next drove to East Moor and walked down to Swanlake Bay, where some of the members examined the Psammosteus Limestone Group (conspicuous by reason of its coarsely-nodular limestone) in the eastern cliffs for plant- and fish-remains; while others traversed the rough foreshore to the exposure of red marl which contains numerous and well-preserved fish-remains (Dittonian). The beds in this hay display also, admirably, the fossil ripple-marks and suncracks which form part of the evidence for the view that sedimentation took place under "continental" conditions. Rejoining the coaches, the party drove to Manorbier and examined marls, sandstones and limestones in the eastern cliffs of the bay, where Psammosteus and other fish-remains, Pachytheca and lowly plants were found in sandstones and shales of the Psammosteus Limestone. The cliffs on each side of Manorbier Bay show many interesting results of differential erosion in deep vertical grooves and trenches locally called" fissures," which are spaces left by the removal of beds of shale and of marl from between hard sandstones. The coastal profiles are those which enter into the general view of the cliffs obtained from Freshwater East, but the shore rock-platform, cut across the edges of vertical beds, is extensively developed on the western side of the bay and merges into remnants of the pre-Raised Beach platform above the present beach. After tea at J\Ianorbier the party drove back by way of Lydstep, Penally and across the St. Florence syncline to Tenby.
Saturday, April 15th. Old Castle Head, Skrinkle Haven, Lydstep Head. The party left Tenby by coaches at 9.15, drove to Skrinkle Farm and walked out to the cliffs at Cunigar Pit, where Mr. Dixon gave an account of recent work done on rocks which have hitherto been grouped as Old Red Sandstone, but which, on account of Mr. W. Wickham King's discoveries of marine lamellibranchs and his investigation of the fish-faunas, may possibly in future be referred to the Silurian (see pp. 217 and 402). The thinly bedded sandstones (Cephalaspis Sandstones) at this point yielded several rostra and fragmentary shields that were identified by Sir Arthur Smith Woodward as Pteraspis crouchi Lank. The party then proceeded to Old Castle Head, which of all points along this coast exhibits most remarkably the gullies, grooves, ribs, trenches, etc., which arise from the differential erosion along bands of tectonic or lithological weakness. The perfect weather conditions permitted the members to examine every part of this headland. A few who clambered down the
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cliff-face into Sandy Hole secured good specimens of Pacbytheca. On the party proceeding to Skrinkle Haven attention was directed to the Ridgeway Conglomerate, the Skrinkle Sandstones (Upper Old Red Sandstone), which here contain one thin marine (Devonian) intercalation, the fossiliferous shales at the base of the Avonian, and the shales and limestones of the lower part of the Cleisiopora zone. After lunch the tide had fallen sufficiently low to permit some members of the party to enter the inner cove beyond the Church Doors limestone. Several good specimens of "Cleistopora ' (Vaughania uetus L. B. Smyth) were collected and the sequence was examined from K2 to the chert beds in the Lower Zaphrentis zone, but the height of the tide did not permit the members to pass through Skrinkle Arch into the innermost cove where the fossiliferous higher beds of this zone are exposed. Leaving Skrinkle Haven somewhat unwillingly the party walked to a fine view-point immediately east of the inlet, and here the general relations of the coast features to the geological structure were demonstrated. The groups of relatively strong and weak beds, developed into promontories and coves in the Old Red Sandstone coast and into saddle and peak features on the Carboniferous Limestone; gash-breccias; ancient solution cavities enlarged into sea caves; and the plateau-like surface of the Carboniferous Limestone in both limbs of the Pembroke-Lydstep-Giltar Point syncline, were all easily discernible. Proceeding past Skomer Saddle (enclosed by a small cliff-castle) the party reached the dry valley which runs down to the shore at Lydstep Caverns. Gash-breccias with interstitial red stalagmitic marls are well displayed in the cliffs of the gorge. Near the head of the beach lies a large norite boulder, probably a glacially transported erratic from the region about St. David's Head. The height of the tide did not permit the western caves to be examined, but most of the party made their way into the great Smuggler's Cave and emerged from the wide vertical shaft which opens upon the hillside from the inner end of this cave. Lydstep Head, between the Caverns inlet and Lydstep Bay, presents many features of great interest to which, however, only a short time could be given. The whole headland exemplifies the plateau-forming tendency of the surface of the Carboniferous Limestone, but the general level is distinctly trenched by a series of incipient saddles eroded along thin beds at the base of the Seminula zone. At Black Mixen (C1 - - C a n i l l i a Oolite-and C2 sub-zones) occurs an exposure of Raised Beach under firmly cemented head, or rubble-drift, and near Whitesheet Rock there is a fine example of the Raised Beach rock-platform, backed by contemporary cliffs all cut in a remarkable mass of gash-breccia which (particularly at the western end of the platform) exemplifies the mode of origin of
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these breccias by the collapse of large caverns. Time did not permit any lengthy examination of the Visean (S- and D-zones) of the headland nor of the chert-debris, including radiolarian cherts from near the base of the Millstone Grit, probably the Eumorphoceras zone, in an old mine-tip opposite Lydstep Lodge. After tea at Lydstep the party rejoined the coaches and drove back to Tenby. In the evening, after dinner at the Cobourg Hotel, Sir Arthur Smith Woodward very kindly gave an address upon the relation of some of the more primitive fishes (lampreys and hag-fishes) of the present day to the Ostracoderm fishes of the Silurian and Old Red Sandstone formations. This address, which summarised recent advances in the study of fishes, was very greatly appreciated by the members as a lucid exposition of problems connected with the evolution of modern fishes.
Sunday, April 16th. Amroth and Saundersfoot. Soon after 9 a.m. a large party of the members made a tour of the more interesting parts of the mediaeval Walls, which were built while the Norman conquest of South Pembrokeshire was being consolidated and which still remain in excellent preservation on the landward side of the town. At 10 a.m. the party left by coach for Amroth, where, the tide being high, attention was first directed to the gaps made in the coast-road by recent storms and to the great shinglebeach heaped across the mouths of the valleys on each side of Amroth. The western stream passes through the shingle by means of a culvert, but the eastern stream, which has no open outlet, percolates through the shingle below New Inn. At Black Hall Point some old workings for coal, opened in the face of the cliff, enabled the party to examine a thin seam underlain by fire-clay containing abundant ironstones. Returning to the western end of Amroth, the party began to study the remarkable cliffs of Coal Measures in this most highly disturbed part of the coalfield. The section prepared by the Geological Survey for the Haverfordwest Memoir had been reproduced in the pamphlet issued in advance of the Field Meeting, and all the structures shown therein could be identified with ease. At the point where the disturbances become most pronounced, Dr. Emily Dix, F.G.S., gave a brief address upon the difficulties involved in any detailed classification of the strata usually termed Millstone Grit and Coal Measures. The beds between Amroth and Saundersfoot belong to Middle Coal Measures (Yorkian). Good collections were made of plant-remains and of lamellibranchs : Carbonicola occurs very abundantly in a light-coloured bed which forms a prominent feature in an anticline west of
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Amroth. The whole range of cliffs presents numerous interesting structural features, one of the most striking being an S-shaped fold in massive sandstones, broken in the middle limb, and passing into an overthrust fault. Beyond 'Wiseman's Bridge the party continued by the mineral railway which runs along the foot of the cliff and passes through the pitching anticline under Hean Castle. This fold is cut by two planes approximately at right angles: (r) the shore-platform, (2) the cliff-face: on each of these surfaces hard sandstones form projections between curving grooves eroded along shales and coal-seams. From the next headland the party walked along the beach past Saundersfoot harbour to examine the steeply-folded anticline below St. Bride's; then, as neither time nor the state of the tide permitted a visit to be made to the buckled anticline at Monkstone, the party returned to Saundersfoot for tea anrl drove thence into Tenby.--(A. L. L.)
Monday, April 17th. North Shore, Tenby and Giltar Cliffs. The party walked to First Point, where Mr. Dixon demonstrated the synclinal structure in which the Farewell Rock and the underlying ripple-marked shales are involved in this headland. The shales and sandstones between First Point and Tenby are greatly disturbed by folds and faults. A bed of shale in the cliff near Middle Rock yielded several goniatites and marine lamellibranchs which may prove to be of value in determining the stratigraphical position of these strata (see pp. 409-II). Continuing along the beach past the brecciated limestones exposed in Barrel-post Rock on a branch of the Ritec overthrust fault, the party reached the group of black shales with limestone bullions, between this rock and Tenby harbour, where in rgo9 Dr. Wheelton Hind collected fossils which led him to regard these beds as representatives of the Pendleside Series. The beds arc now known to belong to the Homoceras zone (Chokier horizon). In the afternoon the party set out across the Burrows towards Giltar Point, where the zonal sequence in the cliffs in the northeastern cliffs of this headland ranges from C, (Cal1il1ia Oolite) to D 1 , the main exposures being in Seminula oolites. The small kitchen-middens amidst the sand-dunes on the summit of the headland were well exposed and several fragments of crude Early Iron Age pottery were found. The date of these middens cannot be exactlv ascertained. From the Point, the members walked westward along the cliff-top noting several very fossiliferous horizons and also the gash-breccias, solution-cavities, blow-holes and cauldrons which occur abundantly in the massive beds of the Seminula zone. Near Valleyfield Top a cliff-section exposes limestones, undisl'ROC. GEOL.
Assoc.,
VOL.
XLIV.,
PART
4,
1933.
26
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THE PRESIDENT AND E. E. L. DIXON,
turbed except for their steady dip, overhanging gash-breccia. Having reached Proud Giltar, an excellent view-point for the Ridgeway, the Pembroke syncline and the coast westward to Old Castle Head, the party turned inland to a quarry in ZI limestones near the Barracks and continued thence by road to Penally village for tea, returning to Tenby by train. In the evening, Mr. W. S. Bisat, F.G.S., who had spent the greater part of the day in First Bay and on the cliffs between First Point and Tenby, exhibited some of the goniatites which he had collected, together with those obtained by other members of the party during the morning, and briefly discussed their bearing on the classification of the highly-disturbed beds immediately north of Tenby.
Tuesday, April 18th. Freshwater West, Linney Head and Stack Rocks. The party left Tenby at 9.15, drove along the Ridgeway to Pembroke, halting there to examine the more interesting parts of the Castle including the Wogan Cavern, and then went on to Bulliber near Castlemartin where they left the coaches and walked down to the shore of Freshwater West near the mouth of Frainslake brook. The Lower Avonian (Tournaisian) limestones here exposed in the southern limb of the Castlemartin Corse anticline (a member of the Orielton compound anticline) afford excellent exposures of highly fossiliferous beds (Z2 and Horizon r). the most productive portions of the section being in the cliffs above Bluckspool. A long fish-spine found here by Dr. Dix has been identified by Prof. Watson as similar to those called Physonemus. To the east of Bluckspool the ground rises to the level of the plateau-like limestone-flat, which extends to Stackpole Head at a fairly uniform level. The cliffs south of Bluckspool and thence to Berry Slade are made up of massive white dolomite, part of a dolomite-reef, some hundreds of feet thick, of CI age and, therefore, correlative with the Waulsortian reefs of Belgium. Near Berry Slade the highest dolomites pass laterally into well-bedded dark limestones and dolomites of standard type. Near Hanging Tar, where the cliff is accessible with care, the succeeding thin-bedded dark limestones and cherts in the lower part of C2 enclose a great lenticle of thick-bedded pale reef-limestone devoid of chert. When deposited, this was clearly a fairly sharp, local elevation on the Carboniferous seabottom. The thin-bedded dark limestones into which the' reef' passes laterally yield an abundant zaphrentid-phase fauna; the reef' is almost unfossiliferous except for fenestellid bryozoa and crinoid-debris. It is, in fact, a bryozoan-reef. Both from the tectonic and from the lithological points of view these cliffs present scenes of great interest. Chert is present
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in enormous quantities, in regular layers of nodules in the thinlybedded limestones, and some of the nodules exhibit curious concentric structures which suggest silicified organisms. Towards Pen-y-holt Bay many folds in the cliffs assume a text-book like clearness and symmetry. The buckled anticline which formerly contained the Cabin Door arch was destroyed several years ago; it was, however, noted that the sea had swept away all the enormous mass of limestone blocks which must have fallen to the shore when this arch collapsed. In this southern district, where no Caninia oolite has been recognised, the highly fossiliferous mudstones and limestones exposed in the cliffs of Mount Sion Down form an undivided series of Upper Syringothyris and Lower Seminula beds (C.-S,). Here and there along the cliff-top, and particularly just west of The Wash, there lie small patches of white quartz gravel, remnants possibly of a Pliocene superficial deposit of fluviatile origin. At numerous points the controlling influence of geological structures upon erosional features is admirably displayed and more especially at such oft-visited scenes as The Wash, Stack Rocks, Green Bridge arch and The Cauldron near Flimston. It was pointed out that the beds in these cliffs, lying west of Flimston Bay, had a gentle northerly dip, whereas at Crocksydam and Bullslaughter Bay, along the same strike, but east of Flimston Bay, the cliffs displayed a steep, buckled syncline (examined at close quarters on the following Thursday). The explanation is that the great Flimston Bay cross-fault, which separates the two ranges of cliffs, effects a huge lateral displacement or ' heave' of the axis of the Bullslaughter Bay syncline. West of the fault the continuation of the axis lies about half-a-mile out of line to the north-west; the northerly-dipping beds so well displayed at The Wash belong to the southern limb of the syncline at a considerable distance from the axis. After tea at Flimston, two points of interest were visited, viz., old pits in pipe-clay (? Aquitanian), where formerly this material was manufactured into bricks, and also the group of large erratic boulders gathered from the surrounding district, and placed for safety in the enclosure surrounding Flimston Chapel by the late Lt.-Col. F. W. Lambton. Two of the largest of these boulders stand as headstones to the graves of Col. Lambton and of his wife, Lady Victoria Lambton. At Flimston the party rejoined the motor-coaches and drove back through Merrion, Monkton and Pembroke to Tenby.
Wednesday, April 19th. Tenby (South Cliffs) and Vicinity. Leaving the hotel at 9.15 the party walked to Castle Hill, an excellent view-point for the prospect across the great syncline
THE PRESIDENT AND E. E. L. DIXON,
in Upper Carboniferous rocks between Tenby and Ragwen Point. From this position also the effects of the Ritec faults upon the rock-outcrops east and north of Tenby can be demonstrated. The zonal sequence in the limestones of the Castle Hill ranges from Upper Zaphrentis-beds with abundant chert nodules in the northern cliffs to brecciated Laminosa-dolomites above the South Beach. The party next visited the local museum housed in a building which incorporates some remnants of the walls of the ancient Castle. In the fore court three erratic boulders of norite from the region about St. David's Head are preserved. Two of these were found recently in excavations in Heywood Lane and Maudlins Road respectively: the third was brought in from Slade near Manorbier. The anticline, which is exposed in the cliffs above the South Sands, can be minutely examined from the beach. The sequence from S1 to C1 in the north limb and the ascending sequence C1 to S2 in the south limb has been fully described in the Memoir and in the Report of the Excursion to Tenby in 1909. On this occasion the beds in each limb were examined as far as the Producttts-bed, in S2' in Rack (or Wreck) Field quarry. After an interval for lunch the party walked along Heywood Lane to Gumfreston Church, one of the most interesting in South Pembrokeshire. Chalybeate springs which issue in the lower part of the churchyard were long ago, possibly in medireval times, enclosed in masonry basins, but they are not now visited for the medical qualities of the waters. They come out near the junction of the Lower and Upper Carboniferous rocks, and a small exposure of limestone near the church has yielded fossils indicative of a high zone of the Main Limestone. From Gumfreston the party walked to Upper Nab Bridge, and after visiting a large glacial erratic which lies on the edge of a disused quarry, and is now almost obscured by an overgrowth of brambles, they crossed the marsh to Holloway where a norite boulder now stands as a gate-post. From this point they proceeded to Hoyle's Mouth or The Hoyle cave which has yielded certain flint and adinole implements of Late Palseolithic forms, and continued to Longbury Bank cave where was obtained the large collection of post-Paleeolithic relics now preserved in the Tenby Museum. The origin of these caves as channels for drainage from a landsurface which existed before present valleys came into existence was briefly discussed. From this point the members of the party walked into Penally, returning to Tenby by train.-(A. L. L.)
Thursday, April 20th. St. Govan's Head to Stack Rocks. The programme for the day included the examination of that part of the southern limestone plateau which extends from St.
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Govan's Head to Flimston. Leaving Tenby at 9.I5 the party drove through Gumfreston and Carew, Pembroke and Bosherston to St. Govan's Chapel. The cliffs of massive limestone (Dibunophyllum zone) show the controlling influence of the joints upon the forms of the cliff profiles. The party walked out to the extremity of the headland, where a large erratic boulder (probably from a locality in North Wales) lies on the edge of the cliff, and then returned to the chapel where at the marl-pit near the top of the gully Mr. Dixon gave an account of his reasons for considering these reddish clays as deposits of New Red Sandstone age. The chapel stands athwart a gully eroded along a fault-plane, and the adjacent cliffs display good sections in pseudo-breccias and other limestones of the Dibunophyllum zone (D,). From this point the party walked westward along the almost level coastal plateau noting at Stennis Ford, Huntsman's Leap, Bosherston Mere, Crocksydam, etc., many striking features of cliff scenery in which the results of the interplay of structure and denudation could be traced. The small cliff castles at Buckspool Down and on Moody Nose added some archseological interest to this traverse. At Bullslaughter Bay and Crocksydam, a position of great stratigraphical interest, fine exposures of the gashbreccias and of the highest beds of the Dibunophyllum zone (top of Dr and D,) were examined. These beds lie in the steep buckled Bullslaughter Bay syncline, which was seen from the west side of Flimston Bay on the previous Tuesday. At Crocksydam the earth-pressure has sheared intensely the Dj-Iimestcne along the junction with D,. Two beds of oolite in D, are of interest in that their fauna differs from that of the rest of Ds, which is that of a zaphrentid-phase. In both of these oolites fine specimens of oolitic chert have been found, but during the present visit only a few poor examples were obtained. In the cliffs of Flimston Bay, between Bullslaughter Bay and Stack Rocks, other fine examples of gash-breccia are displayed, and some of these have been further broken up or almost pulverised by movement along the great cross-fault (mentioned on Tuesday) that displaces the westward continuation of the Bullslaughtcr Bay syncline. The party, having now reached a position which linked the day's traverse with that of Tuesday, had completed the examination of the whole of the southern plateau between Stackpole Head and Freshwater West. After tea again at Flimston those who had not seen the erratic boulders and the pipe-clay were able to visit them on this occasion. The party then drove back to Tenby.
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Friday, April 21st. Freshwater West and West Angle Bay. On this, the last day, the work to be done lay in the westernmost part of the South Pembrokeshire peninsula, beyond the ground examined on the roth. Leaving Tenby at 9.15 a.m, the party drove through Pembroke to Freshwater West. Corston Beacon, a Bronze Age tumulus, was seen, en route, and at Kilpaison Burrows (sand-dunes), a fine dolmen called the Devil's Quoit. At Freshwater West attention was confined to the neighbourhood of Little Furzenip, in order to compare the sequence with that between Freshwater East and Skrinkle Haven (April 14-15). To the north the Neolithic Submerged Forest, the Bifidus Shales, the Ludlow Series and the lowest Downtonian are to be seen only on the foreshore, and exposures depend on tide and the extent of shore-sand. The' Forest' was found to be fairlv well exposed; also the Bifidus Beds, overlain immediately by the Ludlow Series, but the soft disturbed state of the former precluded successful fossil-hunting. The Ludlow Beds were seen to be chiefly fine breccias and beds with plant fragments (of which some were taken by Professor Lang for examination). Their thinness and the absence of the thick series of sandstones present on the south side of Freshwater East are to be ascribed to the unconformity at the base of the overlying Downtonian (see p. 40 2 ) . As at Freshwater East, the latter commences with conglomerates, and apart from the absence of the A uchenaspis Group, the rest of the Downtonian-Dittonian sequence can be fairly well distinguished. But at Freshwater West, above the basal conglomerate group, which is much thicker, the groups, individually and collectively, are much thinner, and no coarsely nodular limestone is developed in the Psammosteus Limestone. The latter was recognised by means of its abundant fish-fragments, among which a specimen of Anglaspis was found. The limestone is exposed along the northern edge of Little Furzenip, where sandstones become prevalent as the series is ascended. Time did not permit a search for the Cephalaspis Sandstones. The Dittonian was noticeably thin. In support of Wickham King's suggestion that the overlying Ridgeway Conglomerate may be unconformable, it was observed that the Dittonian below the lowest conglomerate, bared clean on the foreshore, was eroded and uneven. The question, however, is not settled thereby, as contemporaneous erosion has almost universally preceded the deposition of each sandstone in the ' Old Red.' The exotic appearance of the Conglomerates, interbedded as they are chiefly with fine-grained red marls, was noticed; also the great development of Skrinkle Sandstones (Upper Old
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Red Sandstone}. The party then returned to KilpaisonBurrows, and thence went on through Angle to West Angle Bay, where the feature of importance was the presence of marine Upper Devonian bands intercalated in the upper part of the Upper Old Red. These bands are best developed on the south side of the bay. The tide prevented their being reached along the foreshore, but, after a scramble, the cove (' Third South Cove ') that displays them in sequence with Km, the Modiola-phase at the base of the Lower Limestone Shales, was gained. Here a typical black limestone with Phychopteria damnoniensis was the lowest marine band accessible at the time; its base penetrates the top of the underlying mudstone irregularly, as though along borings or cracks. In the middle of the cove a half-tide rock affords the best exposure in Pembrokeshire of the red sandy Bryozoan Limestone (cc-typc) in Km. A fine-grained oolite and various other beds between this horizon and the Old Red Sandstone may be paralleled exactly at Skrinkle Haven. The north side was then visited, where a grey bed with coaly laminre is intercalated in the Upper Devonian, but it was put out of reach by the tide. After passing back along the Lower Limestone Shales-which, more noticeably here than elsewhere in Wales, have been well cleaved by the Armorican earth-pressure-the Carboniferous Limestone (Z,) in the middle of the bay was examined. Here the party was fascinated by a colony, covering several square feet, crowded with complete examples of sea-urchins (Palechinus) and crinoids with arms and pinnules attached. Elsewhere in the Pembrokeshire Carboniferous even isolated sea-urchins or crinoids with pinnules are almost unknown. The colony well illustrates the imperfection of the average geological record. Incidentally the colony has been repeatedly trodden on for many years, but seems to have suffered little since it was first noticed in 1912. After a short visit to the old brick-pit, which formerly showed exposures of gravels, loams and clays, with glacial erratics and plant-fragments, tea brought the Easter Field Meeting to a close. (E.E.L.D.).
BY
THE DIRECTORS; THE PRESIDENT AND E. E. L. DIXON, B.Sc., F.G.S. [Received lsi November, 1933.]
THE party assembled at Tenby on the evening of Thursday, April rjth, headquarters being, as on the occasion of the former visit in 1909, at the Cobourg Hotel. About forty members attended and these, with a few friends and local visitors, made a total of nearly fifty who attended during some or all of the series of excursions. Miss G. M. Bauer acted as Secretary for the Meeting. Friday, April 14th.
Freshwater East, Swanlake and Manorbier. Leaving Tenby at 9.15 a.m., the party drove along the Ridgeway to the highest point (about 350 ft. O.D.) where, beside Norchard Beacon barrow, the Directors drew attention to the landscape features and their relation to the 'solid' geology of the district. Continuing thence to Lamphey the party crossed the Pembroke syncline to Freshwater East, where the relation of the valley which here opens to the sea to the denuded Freshwater East anticline was indicated. No exposures of the Ordovician shales, which outcrop in the valley, could be examined, but fossiliferous horizons were accessible in the Silurian (Wenlock Beds-poorly seen and without distinctive fossils-and Ludlow Beds) below the basement-conglomerates of the Old Red Sandstone (Downtonian) in the southern cliffs of the bay. The party studied the outcrops of the Ludlow Beds and Downtonian (A uchenaspis Group) also in the cliffs on the northern side of the bay, and here Prof. W. H. Lang gave an account of his work on the fossil plants in the local Old Red Sandstone. A fine cephalaspid fish which he had found in the A uchenaspis Group and generously presented to Jermyn Street Museum-the most complete specimen of an Old Red fish known from Pembrokeshire, as some of the body-segments were preserved-was identified by Sir Arthur Smith Woodward as a Hemicyclaspis of the Murchisoni group. The beautiful cliffs that extend from Freshwater East to Old Castle Head display the vertical beds in the northern limb of the Freshwater East anticline. Coastal profiles include the elements of (1) plateau, (2) scarp bevelled off along the cleavage with an almost uniform southerly slope of about 30 degrees, (3) shore-platform of recent marine erosion, (4)sea-cliff at the head of this platform. On this occasion, when bright sunlight brought
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out all the varied colours of the rocks, the scenery of the cliffs was admirably displayed. The party next drove to East Moor and walked down to Swanlake Bay, where some of the members examined the Psammosteus Limestone Group (conspicuous by reason of its coarsely-nodular limestone) in the eastern cliffs for plant- and fish-remains; while others traversed the rough foreshore to the exposure of red marl which contains numerous and well-preserved fish-remains (Dittonian). The beds in this hay display also, admirably, the fossil ripple-marks and suncracks which form part of the evidence for the view that sedimentation took place under "continental" conditions. Rejoining the coaches, the party drove to Manorbier and examined marls, sandstones and limestones in the eastern cliffs of the bay, where Psammosteus and other fish-remains, Pachytheca and lowly plants were found in sandstones and shales of the Psammosteus Limestone. The cliffs on each side of Manorbier Bay show many interesting results of differential erosion in deep vertical grooves and trenches locally called" fissures," which are spaces left by the removal of beds of shale and of marl from between hard sandstones. The coastal profiles are those which enter into the general view of the cliffs obtained from Freshwater East, but the shore rock-platform, cut across the edges of vertical beds, is extensively developed on the western side of the bay and merges into remnants of the pre-Raised Beach platform above the present beach. After tea at J\Ianorbier the party drove back by way of Lydstep, Penally and across the St. Florence syncline to Tenby.
Saturday, April 15th. Old Castle Head, Skrinkle Haven, Lydstep Head. The party left Tenby by coaches at 9.15, drove to Skrinkle Farm and walked out to the cliffs at Cunigar Pit, where Mr. Dixon gave an account of recent work done on rocks which have hitherto been grouped as Old Red Sandstone, but which, on account of Mr. W. Wickham King's discoveries of marine lamellibranchs and his investigation of the fish-faunas, may possibly in future be referred to the Silurian (see pp. 217 and 402). The thinly bedded sandstones (Cephalaspis Sandstones) at this point yielded several rostra and fragmentary shields that were identified by Sir Arthur Smith Woodward as Pteraspis crouchi Lank. The party then proceeded to Old Castle Head, which of all points along this coast exhibits most remarkably the gullies, grooves, ribs, trenches, etc., which arise from the differential erosion along bands of tectonic or lithological weakness. The perfect weather conditions permitted the members to examine every part of this headland. A few who clambered down the
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cliff-face into Sandy Hole secured good specimens of Pacbytheca. On the party proceeding to Skrinkle Haven attention was directed to the Ridgeway Conglomerate, the Skrinkle Sandstones (Upper Old Red Sandstone), which here contain one thin marine (Devonian) intercalation, the fossiliferous shales at the base of the Avonian, and the shales and limestones of the lower part of the Cleisiopora zone. After lunch the tide had fallen sufficiently low to permit some members of the party to enter the inner cove beyond the Church Doors limestone. Several good specimens of "Cleistopora ' (Vaughania uetus L. B. Smyth) were collected and the sequence was examined from K2 to the chert beds in the Lower Zaphrentis zone, but the height of the tide did not permit the members to pass through Skrinkle Arch into the innermost cove where the fossiliferous higher beds of this zone are exposed. Leaving Skrinkle Haven somewhat unwillingly the party walked to a fine view-point immediately east of the inlet, and here the general relations of the coast features to the geological structure were demonstrated. The groups of relatively strong and weak beds, developed into promontories and coves in the Old Red Sandstone coast and into saddle and peak features on the Carboniferous Limestone; gash-breccias; ancient solution cavities enlarged into sea caves; and the plateau-like surface of the Carboniferous Limestone in both limbs of the Pembroke-Lydstep-Giltar Point syncline, were all easily discernible. Proceeding past Skomer Saddle (enclosed by a small cliff-castle) the party reached the dry valley which runs down to the shore at Lydstep Caverns. Gash-breccias with interstitial red stalagmitic marls are well displayed in the cliffs of the gorge. Near the head of the beach lies a large norite boulder, probably a glacially transported erratic from the region about St. David's Head. The height of the tide did not permit the western caves to be examined, but most of the party made their way into the great Smuggler's Cave and emerged from the wide vertical shaft which opens upon the hillside from the inner end of this cave. Lydstep Head, between the Caverns inlet and Lydstep Bay, presents many features of great interest to which, however, only a short time could be given. The whole headland exemplifies the plateau-forming tendency of the surface of the Carboniferous Limestone, but the general level is distinctly trenched by a series of incipient saddles eroded along thin beds at the base of the Seminula zone. At Black Mixen (C1 - - C a n i l l i a Oolite-and C2 sub-zones) occurs an exposure of Raised Beach under firmly cemented head, or rubble-drift, and near Whitesheet Rock there is a fine example of the Raised Beach rock-platform, backed by contemporary cliffs all cut in a remarkable mass of gash-breccia which (particularly at the western end of the platform) exemplifies the mode of origin of
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these breccias by the collapse of large caverns. Time did not permit any lengthy examination of the Visean (S- and D-zones) of the headland nor of the chert-debris, including radiolarian cherts from near the base of the Millstone Grit, probably the Eumorphoceras zone, in an old mine-tip opposite Lydstep Lodge. After tea at Lydstep the party rejoined the coaches and drove back to Tenby. In the evening, after dinner at the Cobourg Hotel, Sir Arthur Smith Woodward very kindly gave an address upon the relation of some of the more primitive fishes (lampreys and hag-fishes) of the present day to the Ostracoderm fishes of the Silurian and Old Red Sandstone formations. This address, which summarised recent advances in the study of fishes, was very greatly appreciated by the members as a lucid exposition of problems connected with the evolution of modern fishes.
Sunday, April 16th. Amroth and Saundersfoot. Soon after 9 a.m. a large party of the members made a tour of the more interesting parts of the mediaeval Walls, which were built while the Norman conquest of South Pembrokeshire was being consolidated and which still remain in excellent preservation on the landward side of the town. At 10 a.m. the party left by coach for Amroth, where, the tide being high, attention was first directed to the gaps made in the coast-road by recent storms and to the great shinglebeach heaped across the mouths of the valleys on each side of Amroth. The western stream passes through the shingle by means of a culvert, but the eastern stream, which has no open outlet, percolates through the shingle below New Inn. At Black Hall Point some old workings for coal, opened in the face of the cliff, enabled the party to examine a thin seam underlain by fire-clay containing abundant ironstones. Returning to the western end of Amroth, the party began to study the remarkable cliffs of Coal Measures in this most highly disturbed part of the coalfield. The section prepared by the Geological Survey for the Haverfordwest Memoir had been reproduced in the pamphlet issued in advance of the Field Meeting, and all the structures shown therein could be identified with ease. At the point where the disturbances become most pronounced, Dr. Emily Dix, F.G.S., gave a brief address upon the difficulties involved in any detailed classification of the strata usually termed Millstone Grit and Coal Measures. The beds between Amroth and Saundersfoot belong to Middle Coal Measures (Yorkian). Good collections were made of plant-remains and of lamellibranchs : Carbonicola occurs very abundantly in a light-coloured bed which forms a prominent feature in an anticline west of
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Amroth. The whole range of cliffs presents numerous interesting structural features, one of the most striking being an S-shaped fold in massive sandstones, broken in the middle limb, and passing into an overthrust fault. Beyond 'Wiseman's Bridge the party continued by the mineral railway which runs along the foot of the cliff and passes through the pitching anticline under Hean Castle. This fold is cut by two planes approximately at right angles: (r) the shore-platform, (2) the cliff-face: on each of these surfaces hard sandstones form projections between curving grooves eroded along shales and coal-seams. From the next headland the party walked along the beach past Saundersfoot harbour to examine the steeply-folded anticline below St. Bride's; then, as neither time nor the state of the tide permitted a visit to be made to the buckled anticline at Monkstone, the party returned to Saundersfoot for tea anrl drove thence into Tenby.--(A. L. L.)
Monday, April 17th. North Shore, Tenby and Giltar Cliffs. The party walked to First Point, where Mr. Dixon demonstrated the synclinal structure in which the Farewell Rock and the underlying ripple-marked shales are involved in this headland. The shales and sandstones between First Point and Tenby are greatly disturbed by folds and faults. A bed of shale in the cliff near Middle Rock yielded several goniatites and marine lamellibranchs which may prove to be of value in determining the stratigraphical position of these strata (see pp. 409-II). Continuing along the beach past the brecciated limestones exposed in Barrel-post Rock on a branch of the Ritec overthrust fault, the party reached the group of black shales with limestone bullions, between this rock and Tenby harbour, where in rgo9 Dr. Wheelton Hind collected fossils which led him to regard these beds as representatives of the Pendleside Series. The beds arc now known to belong to the Homoceras zone (Chokier horizon). In the afternoon the party set out across the Burrows towards Giltar Point, where the zonal sequence in the cliffs in the northeastern cliffs of this headland ranges from C, (Cal1il1ia Oolite) to D 1 , the main exposures being in Seminula oolites. The small kitchen-middens amidst the sand-dunes on the summit of the headland were well exposed and several fragments of crude Early Iron Age pottery were found. The date of these middens cannot be exactlv ascertained. From the Point, the members walked westward along the cliff-top noting several very fossiliferous horizons and also the gash-breccias, solution-cavities, blow-holes and cauldrons which occur abundantly in the massive beds of the Seminula zone. Near Valleyfield Top a cliff-section exposes limestones, undisl'ROC. GEOL.
Assoc.,
VOL.
XLIV.,
PART
4,
1933.
26
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turbed except for their steady dip, overhanging gash-breccia. Having reached Proud Giltar, an excellent view-point for the Ridgeway, the Pembroke syncline and the coast westward to Old Castle Head, the party turned inland to a quarry in ZI limestones near the Barracks and continued thence by road to Penally village for tea, returning to Tenby by train. In the evening, Mr. W. S. Bisat, F.G.S., who had spent the greater part of the day in First Bay and on the cliffs between First Point and Tenby, exhibited some of the goniatites which he had collected, together with those obtained by other members of the party during the morning, and briefly discussed their bearing on the classification of the highly-disturbed beds immediately north of Tenby.
Tuesday, April 18th. Freshwater West, Linney Head and Stack Rocks. The party left Tenby at 9.15, drove along the Ridgeway to Pembroke, halting there to examine the more interesting parts of the Castle including the Wogan Cavern, and then went on to Bulliber near Castlemartin where they left the coaches and walked down to the shore of Freshwater West near the mouth of Frainslake brook. The Lower Avonian (Tournaisian) limestones here exposed in the southern limb of the Castlemartin Corse anticline (a member of the Orielton compound anticline) afford excellent exposures of highly fossiliferous beds (Z2 and Horizon r). the most productive portions of the section being in the cliffs above Bluckspool. A long fish-spine found here by Dr. Dix has been identified by Prof. Watson as similar to those called Physonemus. To the east of Bluckspool the ground rises to the level of the plateau-like limestone-flat, which extends to Stackpole Head at a fairly uniform level. The cliffs south of Bluckspool and thence to Berry Slade are made up of massive white dolomite, part of a dolomite-reef, some hundreds of feet thick, of CI age and, therefore, correlative with the Waulsortian reefs of Belgium. Near Berry Slade the highest dolomites pass laterally into well-bedded dark limestones and dolomites of standard type. Near Hanging Tar, where the cliff is accessible with care, the succeeding thin-bedded dark limestones and cherts in the lower part of C2 enclose a great lenticle of thick-bedded pale reef-limestone devoid of chert. When deposited, this was clearly a fairly sharp, local elevation on the Carboniferous seabottom. The thin-bedded dark limestones into which the' reef' passes laterally yield an abundant zaphrentid-phase fauna; the reef' is almost unfossiliferous except for fenestellid bryozoa and crinoid-debris. It is, in fact, a bryozoan-reef. Both from the tectonic and from the lithological points of view these cliffs present scenes of great interest. Chert is present
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in enormous quantities, in regular layers of nodules in the thinlybedded limestones, and some of the nodules exhibit curious concentric structures which suggest silicified organisms. Towards Pen-y-holt Bay many folds in the cliffs assume a text-book like clearness and symmetry. The buckled anticline which formerly contained the Cabin Door arch was destroyed several years ago; it was, however, noted that the sea had swept away all the enormous mass of limestone blocks which must have fallen to the shore when this arch collapsed. In this southern district, where no Caninia oolite has been recognised, the highly fossiliferous mudstones and limestones exposed in the cliffs of Mount Sion Down form an undivided series of Upper Syringothyris and Lower Seminula beds (C.-S,). Here and there along the cliff-top, and particularly just west of The Wash, there lie small patches of white quartz gravel, remnants possibly of a Pliocene superficial deposit of fluviatile origin. At numerous points the controlling influence of geological structures upon erosional features is admirably displayed and more especially at such oft-visited scenes as The Wash, Stack Rocks, Green Bridge arch and The Cauldron near Flimston. It was pointed out that the beds in these cliffs, lying west of Flimston Bay, had a gentle northerly dip, whereas at Crocksydam and Bullslaughter Bay, along the same strike, but east of Flimston Bay, the cliffs displayed a steep, buckled syncline (examined at close quarters on the following Thursday). The explanation is that the great Flimston Bay cross-fault, which separates the two ranges of cliffs, effects a huge lateral displacement or ' heave' of the axis of the Bullslaughter Bay syncline. West of the fault the continuation of the axis lies about half-a-mile out of line to the north-west; the northerly-dipping beds so well displayed at The Wash belong to the southern limb of the syncline at a considerable distance from the axis. After tea at Flimston, two points of interest were visited, viz., old pits in pipe-clay (? Aquitanian), where formerly this material was manufactured into bricks, and also the group of large erratic boulders gathered from the surrounding district, and placed for safety in the enclosure surrounding Flimston Chapel by the late Lt.-Col. F. W. Lambton. Two of the largest of these boulders stand as headstones to the graves of Col. Lambton and of his wife, Lady Victoria Lambton. At Flimston the party rejoined the motor-coaches and drove back through Merrion, Monkton and Pembroke to Tenby.
Wednesday, April 19th. Tenby (South Cliffs) and Vicinity. Leaving the hotel at 9.15 the party walked to Castle Hill, an excellent view-point for the prospect across the great syncline
THE PRESIDENT AND E. E. L. DIXON,
in Upper Carboniferous rocks between Tenby and Ragwen Point. From this position also the effects of the Ritec faults upon the rock-outcrops east and north of Tenby can be demonstrated. The zonal sequence in the limestones of the Castle Hill ranges from Upper Zaphrentis-beds with abundant chert nodules in the northern cliffs to brecciated Laminosa-dolomites above the South Beach. The party next visited the local museum housed in a building which incorporates some remnants of the walls of the ancient Castle. In the fore court three erratic boulders of norite from the region about St. David's Head are preserved. Two of these were found recently in excavations in Heywood Lane and Maudlins Road respectively: the third was brought in from Slade near Manorbier. The anticline, which is exposed in the cliffs above the South Sands, can be minutely examined from the beach. The sequence from S1 to C1 in the north limb and the ascending sequence C1 to S2 in the south limb has been fully described in the Memoir and in the Report of the Excursion to Tenby in 1909. On this occasion the beds in each limb were examined as far as the Producttts-bed, in S2' in Rack (or Wreck) Field quarry. After an interval for lunch the party walked along Heywood Lane to Gumfreston Church, one of the most interesting in South Pembrokeshire. Chalybeate springs which issue in the lower part of the churchyard were long ago, possibly in medireval times, enclosed in masonry basins, but they are not now visited for the medical qualities of the waters. They come out near the junction of the Lower and Upper Carboniferous rocks, and a small exposure of limestone near the church has yielded fossils indicative of a high zone of the Main Limestone. From Gumfreston the party walked to Upper Nab Bridge, and after visiting a large glacial erratic which lies on the edge of a disused quarry, and is now almost obscured by an overgrowth of brambles, they crossed the marsh to Holloway where a norite boulder now stands as a gate-post. From this point they proceeded to Hoyle's Mouth or The Hoyle cave which has yielded certain flint and adinole implements of Late Palseolithic forms, and continued to Longbury Bank cave where was obtained the large collection of post-Paleeolithic relics now preserved in the Tenby Museum. The origin of these caves as channels for drainage from a landsurface which existed before present valleys came into existence was briefly discussed. From this point the members of the party walked into Penally, returning to Tenby by train.-(A. L. L.)
Thursday, April 20th. St. Govan's Head to Stack Rocks. The programme for the day included the examination of that part of the southern limestone plateau which extends from St.
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Govan's Head to Flimston. Leaving Tenby at 9.I5 the party drove through Gumfreston and Carew, Pembroke and Bosherston to St. Govan's Chapel. The cliffs of massive limestone (Dibunophyllum zone) show the controlling influence of the joints upon the forms of the cliff profiles. The party walked out to the extremity of the headland, where a large erratic boulder (probably from a locality in North Wales) lies on the edge of the cliff, and then returned to the chapel where at the marl-pit near the top of the gully Mr. Dixon gave an account of his reasons for considering these reddish clays as deposits of New Red Sandstone age. The chapel stands athwart a gully eroded along a fault-plane, and the adjacent cliffs display good sections in pseudo-breccias and other limestones of the Dibunophyllum zone (D,). From this point the party walked westward along the almost level coastal plateau noting at Stennis Ford, Huntsman's Leap, Bosherston Mere, Crocksydam, etc., many striking features of cliff scenery in which the results of the interplay of structure and denudation could be traced. The small cliff castles at Buckspool Down and on Moody Nose added some archseological interest to this traverse. At Bullslaughter Bay and Crocksydam, a position of great stratigraphical interest, fine exposures of the gashbreccias and of the highest beds of the Dibunophyllum zone (top of Dr and D,) were examined. These beds lie in the steep buckled Bullslaughter Bay syncline, which was seen from the west side of Flimston Bay on the previous Tuesday. At Crocksydam the earth-pressure has sheared intensely the Dj-Iimestcne along the junction with D,. Two beds of oolite in D, are of interest in that their fauna differs from that of the rest of Ds, which is that of a zaphrentid-phase. In both of these oolites fine specimens of oolitic chert have been found, but during the present visit only a few poor examples were obtained. In the cliffs of Flimston Bay, between Bullslaughter Bay and Stack Rocks, other fine examples of gash-breccia are displayed, and some of these have been further broken up or almost pulverised by movement along the great cross-fault (mentioned on Tuesday) that displaces the westward continuation of the Bullslaughtcr Bay syncline. The party, having now reached a position which linked the day's traverse with that of Tuesday, had completed the examination of the whole of the southern plateau between Stackpole Head and Freshwater West. After tea again at Flimston those who had not seen the erratic boulders and the pipe-clay were able to visit them on this occasion. The party then drove back to Tenby.
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Friday, April 21st. Freshwater West and West Angle Bay. On this, the last day, the work to be done lay in the westernmost part of the South Pembrokeshire peninsula, beyond the ground examined on the roth. Leaving Tenby at 9.15 a.m, the party drove through Pembroke to Freshwater West. Corston Beacon, a Bronze Age tumulus, was seen, en route, and at Kilpaison Burrows (sand-dunes), a fine dolmen called the Devil's Quoit. At Freshwater West attention was confined to the neighbourhood of Little Furzenip, in order to compare the sequence with that between Freshwater East and Skrinkle Haven (April 14-15). To the north the Neolithic Submerged Forest, the Bifidus Shales, the Ludlow Series and the lowest Downtonian are to be seen only on the foreshore, and exposures depend on tide and the extent of shore-sand. The' Forest' was found to be fairlv well exposed; also the Bifidus Beds, overlain immediately by the Ludlow Series, but the soft disturbed state of the former precluded successful fossil-hunting. The Ludlow Beds were seen to be chiefly fine breccias and beds with plant fragments (of which some were taken by Professor Lang for examination). Their thinness and the absence of the thick series of sandstones present on the south side of Freshwater East are to be ascribed to the unconformity at the base of the overlying Downtonian (see p. 40 2 ) . As at Freshwater East, the latter commences with conglomerates, and apart from the absence of the A uchenaspis Group, the rest of the Downtonian-Dittonian sequence can be fairly well distinguished. But at Freshwater West, above the basal conglomerate group, which is much thicker, the groups, individually and collectively, are much thinner, and no coarsely nodular limestone is developed in the Psammosteus Limestone. The latter was recognised by means of its abundant fish-fragments, among which a specimen of Anglaspis was found. The limestone is exposed along the northern edge of Little Furzenip, where sandstones become prevalent as the series is ascended. Time did not permit a search for the Cephalaspis Sandstones. The Dittonian was noticeably thin. In support of Wickham King's suggestion that the overlying Ridgeway Conglomerate may be unconformable, it was observed that the Dittonian below the lowest conglomerate, bared clean on the foreshore, was eroded and uneven. The question, however, is not settled thereby, as contemporaneous erosion has almost universally preceded the deposition of each sandstone in the ' Old Red.' The exotic appearance of the Conglomerates, interbedded as they are chiefly with fine-grained red marls, was noticed; also the great development of Skrinkle Sandstones (Upper Old
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Red Sandstone}. The party then returned to KilpaisonBurrows, and thence went on through Angle to West Angle Bay, where the feature of importance was the presence of marine Upper Devonian bands intercalated in the upper part of the Upper Old Red. These bands are best developed on the south side of the bay. The tide prevented their being reached along the foreshore, but, after a scramble, the cove (' Third South Cove ') that displays them in sequence with Km, the Modiola-phase at the base of the Lower Limestone Shales, was gained. Here a typical black limestone with Phychopteria damnoniensis was the lowest marine band accessible at the time; its base penetrates the top of the underlying mudstone irregularly, as though along borings or cracks. In the middle of the cove a half-tide rock affords the best exposure in Pembrokeshire of the red sandy Bryozoan Limestone (cc-typc) in Km. A fine-grained oolite and various other beds between this horizon and the Old Red Sandstone may be paralleled exactly at Skrinkle Haven. The north side was then visited, where a grey bed with coaly laminre is intercalated in the Upper Devonian, but it was put out of reach by the tide. After passing back along the Lower Limestone Shales-which, more noticeably here than elsewhere in Wales, have been well cleaved by the Armorican earth-pressure-the Carboniferous Limestone (Z,) in the middle of the bay was examined. Here the party was fascinated by a colony, covering several square feet, crowded with complete examples of sea-urchins (Palechinus) and crinoids with arms and pinnules attached. Elsewhere in the Pembrokeshire Carboniferous even isolated sea-urchins or crinoids with pinnules are almost unknown. The colony well illustrates the imperfection of the average geological record. Incidentally the colony has been repeatedly trodden on for many years, but seems to have suffered little since it was first noticed in 1912. After a short visit to the old brick-pit, which formerly showed exposures of gravels, loams and clays, with glacial erratics and plant-fragments, tea brought the Easter Field Meeting to a close. (E.E.L.D.).