Geological Society of London. 377 



probably sponges, which had grown upon a hard bottom, and afterwards been 

 affected by its mineral constituents. 



Mr. Teal inquired whether the nodules at the base of the Gault had been rolled. 



Mr. Seeley having examined the supposed Crocodile's egg, declared that from 

 its form it could not be that of a Crocodile, and he did not think it was that of a 

 Turtle. It might possibly be the egg of an Ichihyosaw us or Plesiosawus. He 

 stated that he had found nodules of different forms scattered indiscriminately in 

 the Gault, and that his investigations led him to believe that all these nodules had 

 been subjected to wear and tear before coming into their present position. The 

 subdivisions of the Gault recognized at Folkestone would not, he thought, be re- 

 presented elsewhere ; for their mineral characters were found to change greatly 

 towards the west, the Gault itself becoming more sandy and micaceous as it 

 approaches the granitic rocks. He believed that the Blackdown beds represented 

 both the Greensand and tlie Gault. 



Professor Hughes thought that we should take as the base of the Lower Cretaceous 

 Series the first marine beds which succeed the freshwater deposits of the S.E. of 

 England and rest on the Trias and older rocks in the S. W. He considered them 

 to be deposits formed during a considerable period, as successive parts of an irre- 

 gular land-surface were being depressed below the sea ; so that a shore deposit 

 might be formed at Blackdown while fine sand or clay was being thrown down 

 further out to sea over that part of the S.E. of England which had already been 

 submerged to a considerable depth. 



Professor Ramsey observed that the value of such detailed sections, in a palseon- 

 tological point of view, was very great ; and with respect to the physical relations 

 of the Gault and Upper Greensand, he stated that in some parts of England there 

 is lithologically no clear line of demarcation between the two formations ; and in 

 like manner in some other areas there is no very definite boundary line between 

 the Upper Greensand and the Chalk. He then drew attention to the views 

 originally advanced by Mr. Godwin-Austen, who showed that in this part of the 

 world all these Upper Cretaceous formations were deposited over a great con- 

 tinental area that was being slowly submerged, so that while the Upper Greensand 

 began to be -deposited in the sea in one area much of the land still stood above 

 water, and as it got depressed these Greensand strata were gradually deposited on 

 the sinking land. For this reason the two ends, so to speak, of a long section of 

 the Greensand will be of somewhat different age ; and while the end nearest the 

 land was being deposited as sand, further out at sea true Chalk was being formed, 

 and thus much of the Upper Greensand may be considered to have been formed 

 contemporaneously with much of the Lower Chalk under different local conditions 

 of proximity of land and depth of water. 



Mr. Blake believed that the animal oi Amtnonites rostratiis may have lived out- 

 side its shell. 



Mr. Price stated that he did not wish to imply that the divisions indicated in his 

 paper would hold good over wide areas. He added that bones of Turtle were not 

 unfrequent in the Gault. 



Mr. Meyer said that the division between the Gault and Greensand was not 

 distinct. The Beer stone deposited in a hollow to the westward exhibited a 

 change of texture. The upper beds of the Lower Greensand of Folkestone re- 

 present a lower horizon of the Lower Greensand at Guildford. — This was the last 

 Meeting held in the old apartments of the Society in Somerset House. 



II. — May ISth, 1874. — Opening meeting in the New Eooms of 

 the Society in Burlington House. — John Evans, Esq., F.E.S., Presi- 

 dent, in the Chair. — The following communications were read : — 



1. " Note on some of the Generic Modifications of the Plesiosau- 

 rian Pectoral Girdle." By Harry G. Seeley, Esq., F.L.S., E.G.S. 



The author stated that Plesiosauria differ from all living reptilia, 

 except Chelonians, in wanting a sternum, and pointed out the re- 

 semblance between the plesiosaurian coracoid and the coracoid and 

 precoracoid of Chelonians, inferring that the plesiosaiuian scapulee 

 had been carried forward by the potential ossification which elon- 



