OF THE SWISS JUEA AND ENGLAND, 



255 



The lower division of the Callovian, or zone of Ammonites macro- 

 cephalus, as shown in the above table, is regarded by Oppel and 

 Renevier as the equivalent of the Kelloway Rock of England. It 

 is a well-known fact that this rock is local in its development 

 in England, and can only be regarded as the basement bed of the 

 Oxford Clay. In Yorkshire, and again in Wiltshire, this rock con- 

 tains a fairly distinct fauna. A complete list of the fossils from the 

 Kelloway Rock of Yorkshire is given by Mr. Hudleston (Proc. Geol. 

 Assoc. vol. iv. p. 373), and twelve of them are recorded from the ma- 

 crocephalus-zone of the J ura. Very few of these 12 species, however, 

 are peculiar to the Kelloway Rock, since most of them range up 

 into the Oxford Clay. Amm. macrocephcdus itself does not appear in 

 Mr. Hudleston's list referred to above, although a variety is recorded 

 from these beds (Geol. Mag. 1882, p. 147) ; the species is, however, 

 recorded from the Avicula-shales which underlie the Kelloway 

 Rock. These shales also contain Avicula echinata, Mhynchonella 

 concinna ?, and Waldheimia lagenalis, all of which are characteristic 

 of the upper part of the Bathonian of the Jura. 



Dr. Wright gives the following arrangement of the beds which 

 come between the Oxford Clay and the Cornbrash in Wiltshire (Proc. 

 Cotteswold Nat. Club for 1869, p. 207) :— 



Oxford Clay =zone of Amm. Jason. 

 Kelloway Rock =zone of Amm. calloviensis, 

 Kelloway Shale3=zone of Amm. macrocephalus. 

 Cornbrash. 



The fossils recorded from the Cornbrash of Wiltshire (Wright, op. 

 cit. p. 200) include Pholadomya Heraulti, Avicula echinata, A. cos- 

 tata, Terebratula intermedia, and Rhynchonella concinna, all of which 

 occur in, and most of them are characteristic of, the upper beds of 

 the Bathonian of the Jura. Of the fossils which have been collected 

 from the Kelloway beds of this part of England {op. cit. pp. 208 

 and 209) 10 have been found in the macrocephalus- zone of the Jura, 

 but only one of these, viz. Amm. macrocephalus, is peculiar to the 

 Kelloway beds. Several of the oniatus-grou]) of Ammonites occur in 

 the zone of Amm. macrocephalus as well as in the overlying ' Per 

 sous-oxfordien ' ; similarly they appear in the Kelloway beds and in 

 the Oxford Clay. 



In the Bedfordshire district the ornatus Ammonites have been 

 found low down in the Oxford Clay, and the same thing also occurs 

 at Swindon (H. B. Woodward, Q. J. G. S. vol. xlii. p. 295). 



Prom the above remarks, it may safely be stated that the fauna of 

 the Cornbrash links it closely with the upper beds of the Bathonian, 

 and that the lower division of the Callovian (zone of Amm. macro- 

 cephalus) is represented in England by the Kelloway Rock or, 

 when the latter is absent, by the lower beds of the Oxford Clay. 



Thefer sous-oxfordien has many characters in common with the 

 Oxford Clay of England. Lithologically it is almost identical, and 

 there are several species of Ammonites common to both ; and, 

 further, these fossils are preserved under precisely similar conditions, 



