"Vol. 52.] STHATA BETWEEN THE KIMERIDGIAN AND APTIAN. 555 



pains that he had taken in acquainting himself with the details of his 

 subject in every part of Europe. It was entirely beyond the power 

 of the speaker to discuss the broader bearings of the paper, and he 

 could only approach it from a more or less insular standpoint. 

 Moreover, certain criticisms which had suggested themselves to him 

 when the paper first reached his hands, and which he had commu- 

 nicated to Prof. Pavlow, had been very satisfactorily answered by the 

 Author in a letter which the speaker had before him. Yet he must 

 admit that, before finally accepting as the division between the 

 Jurassic and Cretaceous a line so locally inconvenient as that now 

 proposed, which split the Spilsby Sandstone and the Zone D of Speeton, 

 he preferred to await the result of further research. Not to speak of 

 the uncertainty still existing in some parts of Europe, very little 

 was at present known respecting the Infra-Cretaceous rocks of the 

 Middle and South of England, and their relation to those found 

 north of the Wash, and it was his hope that sooner or later he 

 might be able to follow up the Lincolnshire work recently commu- 

 nicated to the Society by investigations farther south, where some 

 elements of the Speeton fauna certainly existed. The recognition 

 of the presence of the Aucellce in Lincolnshire was important. He 

 thought that similar fossils existed at Speeton, but in an inferior 

 state of preservation. He believed that a careful study of the 

 lamellibranchiata would bring out many other points of interest in 

 the fauna in England. 



