Excursion to Eastbourne and St. Leonards. May 23rd and 24th, 1873 - Geologists' Association excursion

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From: A record of excursions made between 1860 and 1890. Edited by Thomas Vincent Holmes , F.G.S. and C. Davies Sherborn, F.G.S. London: Edward Stanford [For the Geologists’ Association], 1891. Source: Cornell University copy on the Internet Archive (Public domain work)

Directors: The Rev. E. S. Dewick, M.A., F.G.S., John Hopkinson, F.G.S., and J. E. H. Peyton, F.G.S. (Report by John Hopkinson.) (Proc. Vol. Hi. P. 2i1.) On arrival, the members at once proceeded to Eastbourne College to inspect the local fossils in the College Museum. This collection was formed by Mr. Dewick, who pointed out some of the more remarkable specimens, and gave a brief account of the succession of the beds in which they were found. After paying a short visit to Dr. Ogier Ward's fine collection of fossils the members visited the Caldecott Museum, where they were received by Mr. F. C. S. Roper and Mr. C. J. Muller, two of the Trustees. There is here preserved an extensive collection of local fossils, a small typical collection of the fossils of other localities, and specimens illustrative of the recent botany and zoology of the neighbourhood, &c., arranged and classified by various members of the Eastbourne Natural History Society. Mr. Roper entertained the party at luncheon, at his residence, Palgrave House.

After luncheon the excavation for the new bath at " The Wish " was inspected. Here an alluvial deposit, containing land and fresh-water shells, antlers of red-deer and roe-deer, and remains of wolf, horse, ox, and pig, is seen to overlie the Gault.

The fine cliff-section of Upper Cretaceous rocks exposed between the Wish and Beachy Head was next examined. The lowest bed seen is the Gault, which is brought up by an anticlinal under the Wish Tower (Martello Tower, No. 74), a small portion only, almost unfossiliferous, being exposed. The Upper Green-sand, with phosphatic nodules, and fossils only in its upper layers, is next seen. It is 30 feet thick, but thins out to about 20 feet at Beachy Head. It is a grey calcareous sandstone, gradually becoming lighter in colour and more calcareous as it passes into the Chalk Marl, which is here very fossiliferous, having a bed of calcareous sponges at its base, then several bands of ammonites, and other fossils in its higher zones.

In the extensive quarries in the Middle Chalk at Holywell, several fossils, including some fine so-called palatal teeth of Ptychodus, were obtained. Here a descent was again made to the shore; and in continuing the walk under the cliff to Beachy Head, the numerous faults and slickensided surfaces of the Chalk, the anticlinal near Cow Gap (which again brings up the Gault and Upper Greensand, the latter here much more fossiliferous than at the Wish), and the landslip which obscures the greater part of this anticlinal, were especially noticed; and at the farthest point reached specimens of Polyzoa and Echinodermata were collected; these abound in the lowest zone of the Upper Chalk, which here forms an almost perpendicular cliff more than 500 feet in height.

The party then returned to Eastbourne by the path along the edge of the cliff, and in the evening attended a meeting of the Eastbourne Natural History Society, at which Mr. Dewick read a paper "On the Alluvial Beds of the Wish," preceded by a brief general account of the geology of Eastbourne.

On Saturday morning the members left Eastbourne for St. Leonards. On their arrival they were met by Mr. Peyton, who had kindly provided carriages for the day. The Old Roar quarry, an extensive excavation in the Wadhurst Clay, was first visited. Here a bone-bed, almost entirely made up of the teeth and bones of the old Wealden reptiles and fishes, is exposed. It appears to have formed the bed of a river, and may at one time have been continuous with the similar bed at the Black Horse quarry, near Battle.[1] Overlying the bone-bed a leaf-bed containing impressions of ferns is seen; and below it the Wadhurst Clay encloses a concretionary argillaceous limestone from three to four feet thick, for which the quarry is worked. Below this is a bed of blue clay; and then another bed of stone, the whole resting on the Ashdown Sand. Two other quarries, one in the upper part of the Ashdown Sand, the other in the Wadhurst Clay, were visited, and in each of them fossils were found.

The beautiful glen of Old Roar especially attracted attention. The stream runs along a fault, and the glen most probably owes its existence to the convergence at this spot of three faults. At Silverhill a fine section of the Tunbridge-Wells Sand was observed; and on the return to St. Leonards the party had an opportunity of observing sections of each of the beds of which the Wealden Series is composed. In descending order these are :—Weald Clay, Tunbridge-Wells Sand, Wadhurst Clay, Ashdown Sand, and Ashburnham Beds[2] the last-named being probably the equivalents of the Upper Purbeck Beds of Dorset-shire. The members were entertained at dinner by Mr. Peyton.

After dinner the party proceeded westward towards Bexhill. The fault by which the Ashdown Sand is let down against the Ashburnham Beds was observed at Bo-Peep Station; and the submerged forest between Bo-Peep and Bulverhithe, which can only be seen when the tide is at its lowest, was next visited. Remains of oak, yew, hazel, and other trees, in their natural position, were seen, and a few hazel-nuts, &c., were collected. On the shore the Ashdown Sand, the mottled clays of the Ashburnham Beds, &c , were successively passed over, and in the Bulverhithe and Bexhill cliffs fine sections of these beds were observed. The sections are very difficult to work out, owing to the faults which traverse them. Numerous specimens of Estheria were obtained from the Ashdown Sand. In a single zone less than a foot thick this little Crustacean is especially abundant.

Tower No. 44 stands on the very edge of a lofty, overhanging cliff of the Ashburn-ham Beds. The mottled clays of this series are seen on the shore at low water, passing upwards into distinctly bedded sandstone, thin seams of lignite being here and there exposed; and just at the top of the cliff are the Ashdown Sands.

Maps

Ordnance Survey. Geological. Sheet 5. 8s 6d.

New Ordnance Survey. Sheets 319, 320, 334. 1s. each.

Books

W. H. Fitton, On the Strata between the Chalk and the Oxford Oolite in the South-East of England. Trans. Geol. Soc., ser. 2, vol. iv. 1836.

W. Topley, Geology of the Weald, 8vo, Landon (Geol. Surv.). 1875. 285.

Papers of the Eastbourne Nat. Hist. Soc. 1873, etc.

References

  1. (Not now to be seen.)
  2. Mr. Peyton informs me that since this excursion took place the Geological Survey has re-named the Ashburnham Beds the "Fairlight Clays, and that " the limestone and shale beds of Rounden Wood, Archer's Hill, Netherfield, &c., which used to be called the greys ' and blues ' of the Ashburnham, are now marked Purbeck," this being settled by the discovery of the gypsum at the Netherfield boring [J. H., 1873.]