^^^' 55-] GEOLO&Y OF THE &REAT CEIfTRlL EAILWAY. 



71 



other parts of the country. JN'evertheless, many of the ammonites, 

 and as a rule only the ammonites, have a thin yellow coating of iron- 

 pyrites. Some of the larger organisms are covered with Serpula^ 

 Anomia^ etc., and others are much worn or decomposed, or pierced 

 by boring-molluscs. 



Most of the fossils recorded from this zone were obtained from 

 the banks of the cutting after they had been sloped, but a few of 

 the interesting small specimens came from two or three heaps of 

 clay near the bridge, the residue of trial-holes. 



The ammonites especially characteristic of this zone that I 

 obtained were: — Ammonites oxynotus^ Quenst. (large and small); A, 

 Guibalianus, d'Orb. (all small) ; A. GreenougM, Sow. ; A. Simpsoni, 

 Bean ; A. globosus, Quenst. ; A. trivialis, Simps. ; A, polymorphuSj 

 Quenst. (not A. trivialis, Simps.) ; A. bifer, Quenst. ; A. planicosta^ 

 Sow. (or between A. planimsta and A. hifer) ; A. raricostatus, Ziet. ; 

 and A. tardecresceiis^ von Hauer. 



{d) Zone of Ammonites raricostatus. 



There can be no doubt, I think, that the zone of Ammonites 

 raricostatus occurs in the district with which we are dealing, 

 although it has not previously been recognized in the Midland 

 Counties. 



At the top of the oxynotus-zone, near the Hillmorton & 

 Dun church Eoad bridge, were found a number of small ammonites 

 very finely and distinctly ribbed. At first I thought that they were 

 all the 3'oiing of A. tardecresceiis, of which species larger specimens 

 were also found ; but, on careful examination, it was seen that the 

 sutures of some were much farther apart than the sutures of 

 others ; those with widely-separated sutures I have referred to 

 A. raricostatus. 



It was not possible to separate this zone distinctly from the 

 oxynotus-zouQ below ; it would also appear that it merges into the 

 armatus-zone above (see list of fossils from the armatus-zone, p. 73). 

 The fossils which I consider justify me in the identification of this 

 zone are : — 



Ammonites raricostatus, Ziet. 



A. tardecresceiis, von Hauer. 



A. nodotianus, d'Orb. 



A. suhplanicosta, Oppel {carusensis, 



dOrb.). 

 A. trivialis^ Simps- 



A. densinodus, Quenst. 

 Gryphcea cymhium, Lam. 

 Cardinia Listeri, Sow. 

 Hippojwdiiim ponderosum. Sow, 

 BhjnchoneLla variabilis, Schl. 

 Spiriferiiia Walcotti, Sow. 



The part of the section within which A. raricostatus was found 

 did not, I should think, exceed 3 or 4 feet (7 or 8 feet on a slope 

 of 20"^). Small nodules seemed to be especially numerous in this 

 7 or 8 feet. 



{e) Zone oi Ammonites armatus (figs. 1-2, pp. QQ & 70). 



The armatus-zone occupies the higher parts of the cutting 

 immediately below the Drift-gravel where any is present, from just 

 north of the Hillmorton & Dunchurch Eoad bridge to about N 



