Vol. 69.] BATHONIAN" ROCKS OF THE OXFORD DISTRICT. 501 



IV. Paleontology. 

 Cornbrash. 



The Cornbrash has yielded a very rich fauna of a constant 

 •character, the same assemblage being found in almost every ex- 

 posure. 



The most noticeable absentees are the Cephalopods, which have 

 only been recorded from AVitney and Woodstock, 1 where M'acro- 

 cephalites macrocephalus and Clydoniceras discus occur. The latter 

 is also recorded from Kidlington. 2 This might be explained by the 

 fact that in most of the exposures only the lower beds are exposed ; 

 but the explanation is not wholly satisfactory, since M. macro- 

 ■cephalus and CI. discus certainly occur very near the base in the 

 Fleet, Weymouth. 



Most of the thirty-seven species mentioned in the Geological 

 Survey Memoir 3 as being the most abundant and characteristic 

 species of the Cornbrash occur ; and of the eighty-eight species 

 recorded, the following fifteen occur in almost every exposure: — 



Pseudomonotis echinata (Sow.). , Pholadomya ddtoidea Sow. 



Gresslya peregrina Phil. Terebratula intermedia Sow. 



Homomya gibbosa Sow. Ornithella obovata (Sow.). 



Modiola imbricata Sow. ! Serpida tricarinata Sow. 



Pleuromya securiformis Phil. 

 Camptonectes lens (Sow.). 

 Pecten vag'ans Sow. 

 Lima gibbosa Sow. 



Echinobrissus clunicidaris (Lhwyd). 

 Py gurus michelini Cott. 

 Anaharia orbit idites Lam. 



Of the eighty-eight species recorded, no less than seventy occur 

 in the Cornbrash of Islip and Kidlington. 4 



Forest Marble. 



The fauna of the Forest Marble is comparatively poor, consisting 

 of but forty species, of which only the following nine are at all 

 common :— 



Camptonectes lens (Sow.). 

 Gervillia waltoni Lye. 

 Modiola imbricata Sow. 

 Pecten fibrosus Sow. 

 Pecten vagans Sow. 



Ostrea sowerbyi Lye. 

 RhynchoneMa concinna auctt. 

 Acrosalenia (spines). 

 Pentacrinus (columnals). 



1 JET. B. Woodward, 'Jurassic Bocks of Britain' Mem. Greol. Surv. toI. iv 

 (1894) p. 446. 



2 J. R Blake, ' Fauna of the Cornbrash ' Monogr. Pal. Soc. 1905, p. 54. 



3 H. B. Woodward, op. supra cit. p. 434. 



4 J. F. Whiteaves, ' Invertebrate Fauna of the Lower Oolites of Oxfordshire ' 

 Rep. Brit. Assoc. 1860 (Oxford) Trans. Sect. p. 107. 



