1868.] JT3DD — SPEETON CLAY. 239 



at the spring tides. Waterwom fragments of this bed are also con- 

 stantly thrown up on the shore of the bay. This group consists 

 of very finely laminated, dark- coloured, bituminous clay, or rather 

 shale, interstratified with hard slaty beds, occasional septaria being 

 scattered through the mass. The beds are crowded with fossils, 

 which, however, are always compressed between the laminae, and 

 are seldom capable either of identification or preservation. The 

 Ammonites, which are particularly abundant, are referable to A. 

 hiplex, Sow., and other species of the group of Planulati, which are 

 characteristic of the continental White Jura. Discina latissima, Sow. 

 sp., Lingula ovalis, Sow., with many bivalves, and some univalves, 

 also occur in great abundance. 



c. Innoceramus, sp. 

 c. Cardium, sp. 



(Numerous species of bivalves). 

 C Discina latissima, Sow. sp. 

 C. Lingula ovalis, Sow. 



Fossils of the Upper Kimmeridge of Speeton. 



c. Icthyosaurus (vertebrae). 

 C. Ammonites biplex, Sow. 

 C. . Several species of the group 



oi Planulati, but too much crushed 



for identification. 

 r. Ostrea, sp. 



In pointing out the relations of this division of the Speeton Clay, 

 I may be permitted to call attention to the very admirable classi- 

 fication of the Kimmeridge beds, proposed by Dr. Waagen * in 

 1865. Having had the opportunity of comparing this classification, 

 not only with the beds of flingstead Bay in Dorsetshire, which the 

 author employs as his typical section, but also with the Kimme- 

 ridge of Lincolnshire, which is very extensively and completely 

 developed, and now with the equivalent beds in Yorkshire, I am 

 convinced that no other arrangement hitherto proposed represents 

 so faithfully, at least as far as this country is concerned, the true 

 palseontological relations of the Upper Jurassic strata. 



The laminated bituminous clays which I have described as oc- 

 curring at Speeton agree very closely, both in mineral characters and 

 in their fossils, with theUpper Kimmeridge (Region oi Discina latissima 

 and Acanthoteuthis speciosa of Dr. Waagen) of Dorsetshire and Lin- 

 colnshire. Everywhere these beds are characterized by the abun- 

 dance of Discina latissima f, Lingula ovalis, and certain Ammonites 

 of the group of the Planulati. 



P. Middle Kimmeridge — The beds of this zone are exposed at a 

 number of places in the cliff", commencing near Mile Haven, and 

 extending along the shore for about a mile to the southwards. 

 They consist of light-blue, somewhat sandy clay, of the kind called 

 by workmen " dicey " — that is, breaking up into more or less regu- 

 lar quadrangular fragments ; a few septaria are scattered through 

 this clay. Towards the upper part the beds become darker in co- 

 lour, laminated in structure, and frequently contain much pyrites. 



* Versuch einer allgemeinen Classification der Schichten des oberen Jura 

 Miinchen, 1865. 



t Sowerby's original specimens of Discina (Patella) latissima were obtained 

 from beds similar to those I have been describing, at Bolingbroke, Lincoln- 

 shire. 



