360 



J. F. BLAKE AXD W. H. HT7DLEST0X OX 



The jamming ton railway-cutting affords the thickest section of 

 the Upper Calcareous Grit to be found in Yorkshire. It is usually 

 a porous fine-grained stone, in parts almost devoid pf lime. The 

 beds are thick, and rather blue-centred. Although there has not 

 been time to weather out the true structure, we have indications of 

 huge doggers in the upper beds, and of the tuberous and branching 

 forms so common at Pickering. It lies with perfect regularity upon 

 the smooth even surface of the Coral Rag. Ammonites were fre- 

 quently met with, especially in the upper beds, during the excava- 

 tion of the line ; we have not had the good fortune to meet with any 

 of the large ones, and are thus unable to say how far they corre- 

 spond with those of the Kirkdale cutting (see page 348). Small 

 interior whorls, such as would be called " hiplex" were common, 

 and may also now be picked up on the fields. It does not appear 

 that the formation is rich in the smaller Mollusca in this neigh- 

 bourhood, as the following small list will show. BeJemnites (phrag- 

 mocones of B. abbreviatus or of B. nitidus), Ammonites, sp. (cf. Thur- 

 manni, Cont.), a very involute form, A. bvpleos (small interior whorls), 

 A. cdternans, Yon Buch (A. serratus. Sow.), Pecten midas, D'Orb., 

 Modiola cancellata, Rom. This last shell is not unlike the Modiola 

 pulchra of Phillips (figured as a Kelloway fossil, pi. v. fig. 26). In 

 Yorkshire it is usually indicative of a high position in the Corallian 

 series, being found in the Hildenley limestone. We have already 

 recorded it from the great shell-beds of Highworth, and of the 

 Lamb-and-Flag in the ^Yilts-Berkshire area. 



The Coral Rag of the Oswaldkirk district, especially about Nun- 

 nington, is rendered very interesting by the quantity of Thecosmilia 

 which it contains, and also by the profusion of spines of Cidaris 

 Jlorigemma. The varieties of Coral are perhaps more considerable 

 than is generally the case in Yorkshire, as we frequently meet with 

 Monilivcdtia dispar and Stylina tubulifera, besides the more common 

 reef-building forms : in these respects it differs much from the 

 Cidaris-Smithii Rag of Seamer-Brompton, chiefly remarkable for 

 Thamnastrcea concinna and Bhabdopliyllia. 



The principal fossils noted are : — 



Natica clio, PS Orb. 

 Cheinnitzia (short form of hed- 



dingtonensis, Sow.). 

 Nerinasa fasciata, Voltz. 

 Littorina muricata, Sow. 

 Ostrea gregaria, Sow. 



Moreana, Buvig. 



Exogyra nana, Sow. 



Pecten vimineus, Sow. 

 Lima pectiniformis, Sow. 

 Modiola inclusa, Phil. 

 Cidaris florigemma, Phil. 

 Ilemicidaris intermedia, Flem. 

 Stomechimis gyratus, Ag. 

 Glyptic hieroglyphicus, Ag. 



The Corallian district just described is prolonged for about 2 miles 

 further eastward in the singular Cauklass promontory, which may 

 be said to run out into a sea of Kimmeridge Clay at the Point of 

 Ness, a name significant of the physical features, which are the 

 result of the sudden termination of the various Corallian limestones 

 and Upper Calcareous Grit. There are some exceptional characters 

 to be noted in the quarries of this district, where a complete section 



