Geological Society of London. 91 



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 paleeontological 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 1886, 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 watei'. In his communication to the 

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

 pebble-bed at the base of the Folkestone 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 Surve}^ is here sandy throughout, there are gravels 

 obviously deposited by a considerable stream consisting chiefly of 

 Lower Greensand chei't (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 Greensand 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 the west formerly existed over 

 the Weald to the south of Dorking, and that the fragments now 

 lying about the surface have been left by denudation, as described 

 by Dr. G. J. Hinde {op. cit). Since, however, as has been stated, 

 the present Lower Greensand escarpment to the north consists 

 of " sandy beds " only, there must be a lithological change from 

 south to north (deep-water beds to shallow). 



Part 2 of the paper is devoted to the district east of the Mole. 

 Where the escarpment rises above the alluvium of the river the 



