PROCEEDINGS OE THE GEOLOGICAL SOCIETY. 5 



the above were founded on teeth. A vertebra of Lamna and a fish- 

 spine were also described, and the collection contained a specimen 

 regarded by the author as a fragment of a Eeptilian tooth. 



Discussion. 



Prof. Seeley remarked that it was difficult to speak about such 

 specimens as were exhibited in illustration of this paper without a 

 more careful study of them. The specimens presented a very 

 striking resemblance to well-known European forms, and in fact it 

 seems doubtful whether specific names should be given to forms so 

 imperfectly known. As regarded the new species of Myliohatis, 

 even when we had the whole palate of a Ray, it was by no means 

 an easy matter to determine it specifically, and a single tooth was 

 insufficient for such a purpose. The specimens referred to the 

 genus Notidanus seemed to him to show important differences from 

 the known forms of the genus. 



He thought that the most interesting of all the specimens ex- 

 hibited was that which the Author had rightly regarded as Eeptilian. 

 Unfortunately the specimen was very imperfect, — there was less 

 than half the crown present, and no fang. This specimen was 

 especially interesting as bearing a decided resemblance to Reptilian 

 teeth of Cretaceous age ; from its imperfect state its affinities were 

 certainly dubious, but its characters seemed to suggest a Mosasaurian 

 type. The occurrence of this tooth may therefore be an indication 

 of the survival of a Mesozoic type into Tertiary times. 



Mr. Smith Woodwaed inquired whether the Author had referred 

 to Mr. Lawle5''s Italian work on Carcharodon^ which would suggest 

 no specific difference between the two specimens exhibited. The 

 Notidanus was a typical upper tooth. He also inquired how the 

 author's Lamna plicata differed from L. contortidens of South Caro- 

 lina and Europe. 



The Author thanked Prof. Seeley for his remarks. In reply to 

 Mr. Woodward he stated that he was not acquainted with the 

 North- American Lamna mentioned by him. 



2. " On a recent Section through Walton Common, exposing the 

 London Clay, Bagshot Beds, and Plateau-gravel." By W. H. 

 Hudleston, Esq., E.E.S., E.G.S. 



The following specimens were exhibited : — 



Quartzite boulder, weight about 14 lbs., found in a Coal-seam, 

 Cannock and Rugeley Colliery (Geol. Mag. 1873, p. 2S9), exhibited 

 by the President. 



Specimens of fossil Fish-teeth and spines, from jS'ew Zealand, 

 exhibited by J. W. Davis, Esq., F.G.S., in illustration of his paper. 



Specimens of Sands, Flints, Chert, «S:c., exhibited by W. H. 

 Hudleston, Esq., F.E.S., F.G.S., in illustration of his paper. 



To he substituted for pp, ^ Sf 6 of Proceediiigs of present Volume. 



