240 Geological Society. 



The wonderful preservation of the bones enables the mechanism 

 of the skull, joints, and movements of the limbs to be described. 



The paper deals with the morphology, and institutes comparisons 

 with other types. 



The evidence proves that it is necessary to form a new family, 

 and that OniitJiodesmus has descended from a sub-order which 

 should include Scaphognathus and Dimorjphodon. The Author 

 suggests the withdrawal of these two genera from the Rhampho- 

 rhynchidse, and the formation of a new sub-order; and also that 

 there are three entirely different phases of development shown in the 

 skulls of the known Ornithosauria, which permit of their division 

 into three sub-orders. 



Measurements of the bones are given. 



March 5th, 1913.— Dr. Aubrey Strahan, F.R.S., President, 

 in the Chair. 



The following communications were read : — 



1. 'The " Kelloway Rock " of Scarborough.' By S. S. Buokman, 

 F.G.S. 



The Author has studied the types of ammonites from the Kello- 

 way Rock described by Leckenby, preserved in the Sedgwick 

 Museum, Cambridge, and a series of Yorkshire Kelloway-Rock 

 ammonites from the Museum of Practical Geology, London. 

 He has grouped these ammonites according to their different 

 matrices, and finds that they indicate several different zones. 

 These zones he arranges in sequence, and suggests how they may be 

 compared with the sections of Kelloway Rock of Scarborough given 

 by Leckenby and by Fox-Strangways. The exact order of the 

 zones is, in one or two cases, not considered to be proved, but the 

 paper is offered with the idea of indicating where further work is 

 required. 



An examination of the ammonite fauna of the Yorkshire zones 

 shows that the so-called ' Kelloway Rock ' of Yorkshire is in part 

 contemporaneous with the Oxford Clay of the Midlands and the South 

 of England, and in part contains faunal facies not represented in 

 these areas, but peculiar to Yorkshire so far as England is con- 

 cerned ; they show, however, some affinity with faunal facies in 

 Russia and in Normandy. 



An examination of the list of species of ammonites recorded by 

 Fox-Strangways from the Oxford Clay of Yorkshire shows that the 

 Oxford Clay of Yorkshire itself is not in the main sequential to the 

 Kelloway Rock, but is contemporaneous with it, leading to the in- 

 ference that even in Yorkshire itself part of the Kelloway Rock is 

 only a local manifestation, and that it passes laterally into Oxford 



cla y- 



A table of zones is given, in order to illustrate the contemporaneity 

 of the Kelloway Rock-Oxford Clay deposits of Yorkshire and the 



