1847.] . PRESTWICH ON THE LONDON CLAY. 353 



in the upper as well as the lower jaw. The upper maxillary is 

 provided with three triturating tubercles, as in Edaphodon, but the 

 dentine of which they are composed is confluent, being rolled round 

 Uke a scroll in the substance of the bone, one edge forming the margin 

 of the tooth, the other buried deep in its centre. The premaxillary 

 has long been known to Dr. Buckland, who, I believe, gave it the 

 provisional name Scaphodus. It is a thin, incurved, scalpriform 

 denticle rounded at the cutting edge. It has the lamelliform struc- 

 ture characteristic of the genus, but corresponds with the premax- 

 illaries of the other members of the family in the columnar arrange- 

 ment of the plates, although they are in juxtaposition and not sepa- 

 rated by septa of bone. 



Dental Armature of Edaphodon. 

 b 



a. Passalodon. 

 *. Edaphodon. 

 6". Chimera. 



The alterations which will be required in the arrangement and 

 nomenclature of the fossil Chimaeroids are shown in the opposite 

 table. I have added a species to the genus Ganodus, under the 

 specific name dentatus. It is about the size of Ganodus rugulosus, 

 but differs from that and the other species of the genus in having 

 the cutting edge distinctly notched. 



2. On Kent's Cavern near Torquay. By Edward Vivian, Esq. 



In this paper an account was given of some recent researches in 

 that cavern by a committee of the Torquay Natural History Society, 

 during which the bones of various extinct species of animals were 

 found in several situations. 



May 26, 1847. 



The following communication was read : 



On the main points of Structure and the probable Age of the 

 Bagshot Sands, and on their presumed equivalents in Hamp- 

 shire and France. By Joseph Prestwich, Jun., Esq., F.G.S. 



[In consequence of the intimate connexion between the two following papers, 

 the publication of the first, read 3rd February 1847, (see Proceed, vol. iii. p. 234) 

 was delayed," at the author's request, in order that it might appear together with 

 the paper read this day.] 



