Vol. 69. j THE ' KELL0WAY ROCK ' OF SCARBOROUGH. 159 



from it, but eight of these he also gives as from the Ivellaways Rock. 

 Of the remainder, three more are of the age of the ' Kelloway Rock,' 

 as developed in Yorkshire : that is to say, Ammonites comptoni and 

 A. elizabeihce are species of the ornatum zone, while A. eugenii 

 belongs to the aihleta zone. 



This leaves only four species. Of these, two, A. cordatus and 

 A. vertebralis, are, when correctly identified, species of the Lower 

 Calcareous Grit as developed in the Oxford district. But in the 

 top layer of Oxford Clay, subjacent to the Lower Calcareous Grit, is 

 a fauna with several Cardioceras-like species, which are often in- 

 correctly assigned to A. cordatus and A. vertebralis. Such a fauna. 

 which must be worked out another time, may be indicated by the 

 citation of these species from the Oxford Clay of Yorkshire. 1 



There remain now only two species,^!, veriioni 2 and A. octdatusS 

 By the kindness of the authorities of the York Museum, which 1 

 gratefully acknowledge, the types of these two species have been 

 placed in my hands for study. So far as I know, they are quite 

 peculiar to Yorkshire. They may have lived contemporaneously 

 with the Cardioceras-like species, or they may indicate another 

 date. 4 It will not commit us, then, irretrievably to mark the 

 Oxford Clay of Yorkshire, which is not contemporaneous with 

 the ' Kelloway Rock,' as being of vernoni hemera, until the facts 

 can be more accurately ascertained. 



There is yet another species from the Oxford Clay of Yorkshire, 

 Peltoceras intertextum Simpson sp.° incorrectly assigned to the Lias 

 by its author. But it is a derived fossil and is pyritized, and is, 

 moreover, an Oxford Clay form. It is probably from the aihleta 

 zone, where that zone is argillaceous and not calcareous. My 

 thanks are due to the late Mr. T. Newbitt, F.G.S., and the 

 authorities of the Whitby Museum for kindly allowing me to have 

 the type for study. 



The results of the foregoing remarks may be stated graphically 

 as follows (Table IV, p. 160) :— 



i A flat (? thin) form of the so-called ' Am. cordatus ' is presumably 

 Am. scarburgensis Young & Bird, which is thus described (' Geol. Surv. 

 Yorkshire Coast ' 2nd ed. 1828, p. 265) : — ' We have a small ammonite re- 

 sembling this [A. speetonensis Bean] on the side, but very flat, and with a 

 crenated keel, found by Mr. Williamson in the second shale [Oxford Clay] 

 at Scarborough. This species may be named A. scarlntrffensis.' 



2 ' Geol. Surv. Yorkshire Coast ' 2nd ed. (1828) pi. xiv, fig. 5. 



3 J. Phillips, ' Geol. Yorkshire ' vol. i (1829) p. 138 & pi. v, fig. 16. 



4 In certain MS. lists of Jurassic zones which I drew up for the Geological 

 Survey, I used the term ' -pre-cordatus' for these Cardioceras strata of the Oxford 

 Clay which underlie the Calcareous Grit where C. cordatum occurs. This 

 provisional term was necessary, because there are no correctly identified 

 ammonites to give a name. 



3 ' Fossils of the Yorkshire Lias ' 1855, p. 50. 



