546 Geological Society. 



December 19th. — Dr. Henry Woodward, F.R.S., President, 



in the Chair. 

 The following communications were read : — 

 1. 'The Lower Greensand above the Atherfield Clay of East 

 Surrey.' By Thomas Leighton, Esq., F.G.S. 



This paper embodies the results of the author's examination of 

 the Lower Greensand of East Surrey during the three years 1892-94 ; 

 and it is stated that two papers published by the Geologists' Asso- 

 ciation (vol. xiii. pp. 4 & 1G3) are to be taken as introductory to 

 this one. The area discussed in this paper extends from Leith Hill 

 in the west to Tilburstow Hill in the east ; and the divisions of the 

 Lower Greensand chiefly referred to are those hitherto known as the 

 Bargate, Sandgate, and Hythe Beds. The author states that the 

 Lower Greensand of East Surrey shows that formation to consist of 

 beds deposited in a marine estuary or narrow sea, not far from land 

 and within the influence of strong currents, extending generally 

 from N.W. to S.E., so that, without palseontological evidence, no 

 correlation of beds here with those exposed at Sandgate and at 

 Hythe is possible. He arrives at this conclusion by following the 

 outcrop of the various chert-beds, which, after Dr. G. J. Hinde 

 (Phil. Trans. Roy. Soc. vol. clxxvi. 1885), are accepted as of sponge 

 origin (deep-water deposits), and further by following the outcrop 

 of the pebble-beds, described by Mr. C. J. A. Meyer (Geol. Mag. 

 for 1866, p. 15). 



In Part 1 of the paper the author discusses the district to the 

 west of the Mole, and endeavours to show that the view set forth 

 in the Weald Memoir of the Geological Survey, to the effect that 

 between Dorking and Leith Hill the lower horizons of the Lower 

 Greensand undergo a change in composition, although possibly 

 verbally correct, is geologically incorrect, since the lithological 

 change is from south to north, from beds laid down in deep water 

 to beds laid down in shallow water. In his communication to the 

 Geologists' Association of last year, the author showed that the 

 pebble-bed at the base of the Eolkestone Sands was at Abinger 

 intimately associated with the Bargate Beds ; and he now states 

 that he has identified this pebble-bed in the Dorking-Horsham road 

 section, described by Prof. G. S. Boulger and himself in 1892, and 

 at two other places to the east. The drifts of the same neighbour- 

 hood are then discussed, and it is found that at the top of and on 

 both sides of the Lower Greensand escarpment, which, as stated by 

 the Geological Survey, is here sandy throughout, there are gravels 

 obviously deposited by a considerable stream consisting chiefly of 

 Lower Greensand chert (entirely of Lower Greensand material) with, 

 amongst the rougher material, lenticular beds of fine pebbles composed 

 chiefly of debris from the Bargate Beds. Fragments of Lower Green- 

 sand chert have been obtained from the alluvium or from the beds of 

 the streams now draining the Weald area to the south of Dorking. 

 The soil over the Weald Clay as far south as Holmwood Common 

 has everywhere yielded to the author fragments of the same chert. 

 Hence it is argued that the chert-beds now seen upon Leith Hill to 



