Vol. 6^.~] AND CORALLIAN ROCKS OP BRILL. 49 



least open to objection — where no sections were exposed at the time. 

 As regarded the cause of the occasional absence of the Corallian 

 Oolite over some parts of Oxfordshire and adjoining districts, the 

 speaker's view was that it was owing to denudation at the close of 

 the Oxfordian Period, as the formation itself must be supposed to 

 have been continuous over this region when originally deposited. 



Mr. Whitaker said that the specimens of selenite were inter- 

 esting, especially those of Belernnites in which calcite had been 

 replaced by that mineral. He had found a small specimen of the 

 kind in the Oxford Clay of Buckinghamshire forty-nine years ago, 

 and at a later date had seen many specimens in a pit in the Oxford 

 Clay of the valley of the Ouse, several miles above Bedford, but 

 had never before seen any from the Kimeridge Clay. There was 

 some evidence, from wells, that a stony bed occurred (a little way 

 underground) in the clay-tract southward of Brill ; and it might 

 represent the Arngrove Stone of the Author, although this was very 

 doubtful. 



The Author thanked the Fellows for their reception of his paper, 

 and, in reply to Mr. H. B. Woodward, said that he was not prepared 

 to admit the derived character of the Gryphaza clilatata to which 

 Ostrea deltoidea was attached. 



Q.J.G.S. l^o. 249. 



