158 me. s. s. bttckman ox [June 1913,- 



examined ; but, as Eox-Strangways quotes Ammonites crenaivs 

 from the Kellaways Rock of Yorkshire (p. 277), and as A. 

 crenatus, or rather a Creniceras., is fairly unmistakable, it is 

 reasonable to conclude that there is some trace of the renggeri 

 zone. At the same time, the lack of the associated fauna would 

 seem to indicate a poor development. Its position is presumably 

 in the calcareous shaly rock. 



There remain yet two matrices, two zones, to be accounted for 

 — vertumnus and gregarium : the former answers to Leckenby's 

 calcareous pisolite and the latter to Strang ways's ' hard band, very 

 oolitic ' or to his ' dark-coloured shale with oolitic grains,' which he 

 thinks is the equivalent of Leckenby's rock. At any rate, both 

 authors find this stratum, or these strata, at the top, close under 

 so-called ' Oxford Clay.' 



The vertumnus zone shows a fauna which differs considerably 

 from any fauna found, so far as my experience goes, in the rest of 

 England. 



Aspidoeeras faustum, Quenstedtoceras vertumnus, Q. aff. gregarium r 

 Pachyceras rugosum, Oppelia glabella, Siemiradzkia pocidum are 

 all species which seem to be special to Yorkshire as distinct from 

 the rest of England, leading to the inference that the Oxford Clay 

 deposits of the Midlands and the South are incomplete. A. faustum 

 and S. pocidum are found in Normandy, where also are found 

 species of Pacliyceras allied to P. rugosum. A. faustum is re- 

 markable for its likeness to certain forms of Aspidoeeras found in 

 the Lower Calcareous Grit (basal Argovian) of Oxford and the 

 neighbourhood, but that corresponds to a much higher stratum in 

 Yorkshire. 



The gregarium zone also shows a fauna peculiar to Yorkshire, 

 as compared with the rest of England. Quenstedtoceras gregarium 

 is most like some Russian species. Q. turgidum and Aspidoeeras 

 hirsutum are found in Erance. 



It is obvious that, at present, it is not possible to say which is 

 the higher of the two matrices and the two faunas. The sequence 

 now indicated is a supposition ; but the calling of attention to- 

 it may be the means of obtaining the required solution. It is 

 presumed that these strata represent in a general way the maria> 

 zone of the ]S T ormand5 T coast, and the likeness of Quenstedtocerasr 

 vertumnus to Q. marice favours this view. But I have seen no 

 evidence as yet for any marice fauna in the Oxford Clay of the rest 

 of England. 1 



A few words may now be said about the Oxford Clay of York- 

 shire. Eox-Strangways (op. cit. p. 295) quotes fifteen ammonites- 



1 Identifications of Ammonites marice cannot be accepted -without investi- 

 gation : A. d'Orbigny mixed several forms. (See below, p. 164.) 



