76 DESCRIPTION OF THE COAST. 



the south side of the vale of Pickering, is merely superficial : blue clay 

 is found at too many points in contact with the bottom of the chalk, to 

 leave the slightest doubt on the subject. At Speeton the clay is dark 

 and laminated, with distant layers of nodules of argillaceous ironstone, 

 the larger of which are fissured within, and have these fissures either 

 empty, lined with crystals of selenite and iron pyrites, or filled up with 

 calcareous spar. Such large nodules occasionally contain ammonites and 

 fragments of hamites. The smaller oval nodules frequently enclose small 

 crustaceous animals, having the general appearance of the genus astacus, 

 but with attenuated fore-legs, and slender sub-abdominal processes. A 

 great number of very interesting fossils, which will be described here- 

 after, have at different times been found in the clay at Speeton. Among 

 the most curious, are a fragment of a jaw containing four rows of (molar) 

 teeth in situ, in the possession of its discoverer, C. Preston, Esq. of 

 Flasby, teeth and vertebras of saurian animals, many beautiful ammo- 

 nites, hamites, and nuculae, which ornament the cabinets of Mr. Bean and 

 Mr. Williamson. To make any tolerable collection of the beautiful 

 fossils of Speeton requires patience and assiduity ; for though they are 

 really not scarce, yet it is only after rains have exposed a fresh surface 

 that they can be found in plenty. 



Several remarkable fossils which Mr. Mantell describes from the 

 gault of Sussex, are found at Speeton ; and generally a great analogy may 

 be perceived between the fossils of the blue clay of Speeton and Knap- 

 ton, and those which belong to the argillaceous beds which lie beneath 

 the chalk in Kent and Sussex. But some of the Speeton fossils bear so 

 great a resemblance to those of the Kimmeridge clay, that Professor 

 Sedgewick has been led to refer them to that stratum. The evidence on 

 this subject may be more completely unfolded in the chapter devoted to 

 organic remains ; but, in the mean time, I may state, that my observa- 

 tions lead me to refer at least the upper part of the Speeton clay to 

 the gault of Cambridge and Sussex ; and I have before said that the 

 lower argillaceous range along the north side of the vale of Pickering, 

 belongs, to the Kimmeridge clay. 



