1868.] JUDD SPEETON CLAY. 225 



Not the slightest doubt, however, can exist as to its identity with 

 the species occurring in the Hilsthon, and figured by Komer under 

 the name of Serpula Phillipsii. {Vide Rom. Yerst. nordd. Kreide. 

 p. 102, t. 16. f. 1. Mor. Cat. 2nd ed. p. 94.) 



Spatangus arc/illaceus, Phill., is, on the authority of Agassiz him- 

 self, only a synonym of Toxaster complanatus, Ag., which is probably 

 the most abundant and characteristic of all the Lower Neocomian 

 fossils. ( Vide Appendix B.) 



GaryophylUa conulus, Phil. — I have long doubted the identity of 

 the minute Yorkshire coral with the large and well-marked species 

 from the Gault, figured and described by Milne-Edwards and Haime. 

 Mr. Dallas, who kindly made a comparison for me, found it impos- 

 sible to come to any certain conclusion on the subject, owing to the 

 imperfect state of preservation of the type specimens. 



On the other hand, I shall show that in the highest division of 

 the Speeton Clay a great number of species occur which are emi- 

 nently characteristic of the Lower Greensand and Atherfield Clay, as 

 Perna MuUetii, Desh., Ammonites Deshayesii, Leym., Beleynnites 

 semicanaliculatus (Blain. ?), Nautilus plicatus, Sow., and N. radi- 

 atus, Sow., Exogyra sinuata, Sow., Thetis Sowerhii, Rom., Panopcea 

 plicata, Sow., Panopcea Neocomiensis, Desh., Terehratula sella, Sow., 

 and many others. 



It may perhaps be argued that possibly a representative of the 

 Gault may really exist at the top of the Speeton Clay, though hidden 

 by the unconformable overlap of the Hunstanton limestone ; but, 

 for reasons already given, I consider this highly improbable, and 

 believe the Gault, if not represented by the Red Chalk, to be alto- 

 gether absent from the Yorkshire coast. 



V. Classification of the Beds coNSTiTrTiNG the Speeton Clay. 



A. Upper Neocomian. — Of course, owing to the overlap of the 

 Cretaceous beds, the section of the Speeton Clay is incomplete in its 

 upper part ; and further, as I have already stated, the true junction 

 of the Hunstanton limestone with the clays is always concealed by 

 landslips. 



The highest bed of the series which is visible at Speeton consists 

 of black clays containing small and beautifully crystallized nodules 

 of pyrites, which appear to be always aggregated in nests or irre- 

 gular layers. This bed is nearly destitute of organic remains, the 

 only fossils which I have been able to detect in it up to the present 

 time being small Belemnites, which are always in a fragmentary 

 condition. This black clay is seen at several points along the base 

 of the undercliff of white chalk, as well as in Speeton Gap ; it also 

 makes its appearance in the upper part of Black Cliff, where it is 

 covered by a bed of red chalk rubble (which is probably not far from 

 its original position) ; and, lastly, it is seen in the landslip at the 

 base of the same cliff. 



Below these almost unfossiliferous black clays we find others of 

 a dark- blue colour, in which fossils occur, but are bv no means nu- 



