I 



TRANSACTIONS OF SECTION C. 507 



present aspect of this singular ai-ea — a description of the complex nature of the 

 structure of which would here be out of place. ' What was the condition of the 

 English Channel as to its coast-line when certain marginal accumulations were 

 being formed 'i ' To answer this demands a profound acquaintance with the old 

 physical geography of the district both of Northern France and Southern England. 

 ' T/te Brick-earth. — Above the yellow clay and mammalian gravels, the highest or 

 uppermost deposit on the coast, there occurs a uniform bed of dark chocolate-coloured 

 unstratified clay, averaging about 3 feet in thickness. This clay forms part of that 

 great layer of earthy matter which overlies all the gi-avel and other beds of the 

 Sussex levels, and is extensively used for brickmaking. This brick-earth is a 

 subaerial deposit, probably occurring as the wash of a terrestrial surface under a 

 greater rainfall than we have now. This deposit is conspicuously shown along the 

 shore, and forms the low cliffs of Bracklesham Bay. To this period Mr. Godwin- 

 Austen refers the ' Combe rock ' of Selsea. He then refers to the condition of the 

 English Channel area, at the period of the Crag-deposits of the German Ocean. The 

 author is disposed to the belief that this Channel area was mostly in the condition 

 of dry land at the time that the area of the German Ocean was occupied by the 

 Crag sea. The peculiar molluscan fauna of the Sussex deposits point to a limitation 

 of a marine province in that direction, whilst their habits indicate at the same time 

 shallow water and marginal conditions. The temperatvire of the water of the 

 English Channel during the period of the JEleplias ]mmigenius, and its associates, 

 was such as now occurs 12 degrees or nearly 800 miles further south. In 1871 

 Mr. Alfred Bell examined with great care the fossil contents of the Lutraria clay or 

 mud-deposit ; he has added materially to the hitherto published lists of contents 

 of this deposit. The result proves it to be unique as regards the fauna. ' Of the 

 144 species of shells Mr. Bell states that 30 do not exist nearer than the West of 

 England, the Channel Islands, North of Spain, 8 or 10 not passing this side or 

 north of Gibraltar, all being littoral (or sub-littoral) species. As British Quaternary 

 fossils 45 are peculiar to Selsea, and 20 others probably find here their earliest 

 place in British geological history.' Numerically the contents of this mud-deposit 

 are as follows : mammalia, 5 genera and 6 species ; mollusca (bivalves), 33 genera 

 and 62 species ; univalves, 32 genera and 80 species ; polyzoa, 2 species ; Crustacea, 



8 genera and 10 species ; echinodermata, 2 genera and 2 species ; foraminifera, 



9 genera and 10 species. Most of the fossils occur opposite Thorney coastguaril 

 station, where the Lutraria clay rises at intervals in low hummocks. The elephant 

 remains appear to be those of E. anf.iqwus. The tooth of E. meridionalis has also 

 occurred here, an association resembling the Forest-bed of Cromer. In the Chichester 

 Museum there exists the greater portion of a fine skeleton of E. antiquus obtained 

 from this mud deposit. 



I have thus dwelt at some length upon these post-Pleiocene or Pleistocene beds 

 at Selsea, owing to their local interest, and hope by so doing to induce any present 

 who may be interested in the Quaternary geology of the British Islands, especially 

 that of Sussex, to visit Bracklesham Bay and Selsea, near to which we are now 

 assembled. 



The Eocene Fokmations op Selsea and Bkackleshasi Bat. 



It is impossible to pass unnoticed the Eocene tertiaries that occur in Brackles- 

 ham Bay, the stratigraphical position of which has long been settled, comprising 

 the middle portion or fossiliferous division of the Bagshot Series. The Bracklesham 

 beds take their name from the Bay in which they are so characteristically developed, 

 yet difficult to clearly imderstand. The main divisions extend fi-om Wittering, 

 on the west, to the Barn Rocks, east of Selsea Bill, a distance of seven miles. 



The Hampshire basin alone, in England, contains the nummulitic series, no 

 fossiliferous representative being known in the London basin. 



About a mile to the east of Selsea Bill is situated the ' Park bed.' This Park bed 

 is analogous or equivalent to the 'Calcaire grossier' of Grignou, in the Paris basin.' 

 It contains thousands of Nummulina laevigata associated with Perna, Bulla, Cyprrea, 



*• ' Four hundred species of Mollusca have been found in the French deposits. 



