180 Reports c£' Proceedings — Geological Society of London. 



(Lapworth), and OholeUa (?) aff . salteri, Holl. They are traversed by 

 two sills of olivine-basalt. The uppermost 50 feet are stained red. 

 The following new reading of the Bletchley boring is proposed : — 



Feet. 

 Oxford Clay . . . .192 

 Forest Marble .... 33 

 Lias (Charmouthian) . . 185 



Au attempt is made to express the depth of the Palaeozoic floor by 

 a contoured map, and its possible constitution and tectonic structure 

 are discussed. 



2. "On the Skeleton of Ornithodesmus latidens, an Ornithosaur 

 from the Wealden Shales of Atherfield (Isle of Wight\" By 

 Reginald Walter Hooley, F.G.S. 



The bones were obtained from blocks recovered from the sea after 

 being washed from a huge fall of tlie Wealden Shales. Portions of 

 the skeleton missing in the Atherfield specimens are supplemented by 

 bones in the British Museum (Natural History), No. 11/176, upon 

 which the late Professor H. G. Seeley founded the genus. There are 

 remarkable peculiarities in the skull which isolate it from all known 

 families, such as the presence of a sixth vacuity and a transposition of 

 the jugal and qiiadratojugal in regard to the supi'a- and infra-temporal 

 arcades. The jugal is excluded from the upper arch, and the jugal 

 and quadratojiigal from the lower, which is formed entirely by the 

 quadrate. The orbits are placed far back in the skull, and the 

 quadrate articulation is much in front of them. The occiput is 

 concave. Teeth occur only at the extremity of the long muzzle ; they 

 are set close together, and those of the upper jaw interlock with those 

 of the lower jaw. The notarium, the humerus, the decussation of the 

 ulna by the radius, the sternum, and femur all show divergence from 

 other types. 



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 Ornitliodfsmus has descended from a sub-oider which should 

 include Scaphogyiathus and Diinorphodon. The author suggests the 

 withdrawal of these two genera from the Rhamphorhynchidae, and the 

 formation of a new sub-order ; and also that there are three entirely 

 diiiei-eut 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. 



Annual Gknekal Meeting. 



February 21, 1913.— Dr. Aiibrey Strahan, F.R.S., President, 

 in the Chair. 



The Reports of the Council and of the Libi'ary Committee were 

 read. Of the 63 Fellows elected in 1912, 43 paid their admission 

 fees before the end of tliat year, making, with 13 previously elected 



