136 Reports and Proceedings— 



by paucity of species and great abundance of individuals. It is thickest 

 in Dorsetshire and Lincolnshire, but thin or absent in the inland 

 counties. The author stated that no Fauna comparable with that of 

 the Middle Kimmeridge or " Pterocerien" has been discovered in Eng- 

 land, though some of its less characteristic fossils occur- associated with 

 Lower-Kimmeridge forms. The Lower Kimmeridge is a mass of blue 

 or sandy clay, with numerous calcareous "doggers," largely developed 

 in Lincolnshire, the whole representing the "Astartien" of foreign 

 geologists. Its thickness is estimated at from 300 to 500 feet in Ring- 

 stead Bay, and. about 400 feet in Lincolnshire. The fossils of the 

 Coral Rag extend up into the Kimmeridge passage-beds, which are 

 typically developed at Weymouth, where they are about 20 feet thick. 



Discussion. — Prof. Seeley complimented the author on the elaborate palssonto- 

 logical details which he had correlated in his paper. He noticed that the Kim- 

 meridge Clay is thinnest in the neighbourhood of Ely, and thickens to the north, 

 in Lincolnshire, and also southward, and that this southward thickening is con- 

 comitant with a development of sandy beds at the base and less markedly also at 

 the top. As the formation is traced into France by way of Boulogne, the sandy 

 characters become more strongly marked, and eventually the deposit can no longer 

 be recognized as a Clay, though westward, at Havre, it is as much a clay 

 as at Weymouth. He then called attention to the fact that in France 

 there is a large curve of igneous rocks, roughly parallel to the present out- 

 crop of the English Secondary strata, partly broken through by a mass of 

 Palaeozoic rocks, extending northward from Strasburg through Belgium, and by 

 way of Harwich towards the Cambridgeshire area. He thought that the denuda- 

 tion of these deposits probably furnished the materials of the southern portion of 

 the beds under consideration ; and if so, the stratigraphical sequence becomes in- 

 telligible in this way, — the Kimmeridge Grit, being sandy, resulted from an eleva- 

 tion of this igneous curve, and the mass of the Kimmeridge indicated that the curve 

 was depressed so that the sand did not reach the British area, while the covering 

 sand shows that it was again upheaved. The bottom sand is in physical con- 

 tinuity with the upper Calcareous Grit, and the upper sand is similarly continuous 

 with the Portland Sand, so that he doubted whether any portion of the series is 

 really wanting in England. 



2. "Note on Pelobatochelys Blakei and other Vetebrate Fossils 

 obtained by the Rev. J. F. Blake from the Kimmeridge Clay." By 

 Harry Govier Seeley, Esq., F.L.S., F.G.S., Professor of Physical 

 Geography in the Bedford College, London. 



The author stated the fossils referred to in his paper gave evidence 

 of three species of Ichthyosaurus (one larger than any previously 

 known to occur in the formation), a Pliosaurus, a Steneosaurus, a 

 small Ornithosaurian, and a species of Chelonian, which he described 

 under the name of Pelobatochelys Blakei. The remains of this animal 

 indicated a carapace sixteen inches long by fourteen inches broad, and 

 angularly arched posteriorly. The pygal scute was divided as in 

 EmySj and the hinder margins of the vertebral scutes were elevated as 

 in some species of Batagur. The vertical scutes were nearly twice as 

 broad as long, and interlaced with each other by sawlike margins. 

 The costal plates were imperfectly ossified. 



3. " On the Cambridge Gault and Greensand." By A. J. Jukes- 

 Browne, Esq., F.G.S. 



This paper has for its object to determine the true position of the 

 Cambridge nodule-bed in the Cretaceous series, and to investigate the 

 nature and origin of its peculiar fauna. 



