88 DESCRIPTION OF THE STRATA. 



shale, appearing in ferruginous veins and patches ; as may be seen in 

 Whitestone cliff, and at Scarborough castle. Calcareous minerals, 

 particularly selenite and gypsum, are also not uncommon in these beds. 

 Numerous crystals of selenite occur in the Gristhorp cliffs, especially 

 Avhere the schist is most argillaceous. Thin veins of fibrous gypsum 

 traverse the shale in various places; of which instances are seen at 

 Scarborough castle. Some of the specimens have a pearly lustre. 



Organic remains are not so abundant in these strata as in the 

 upper shale: yet in some places, particularly in the dark coloured 

 clay at Gristhorp, they are numerous. They consist principally of 

 shells, with some fragments of wood. The sandstone that alternates 

 with the shale partakes of its petrifactions. It contains pieces of wood, 

 sometimes of a considerable size, as well as fragments of charcoal: 

 and the beds of this kind between Cayton mill and Scarborough, 

 mentioned above, may be considered as belonging to this class, more 

 than to the sandstone of the upper series ; though, where the strata 

 are so much broken, there must be a mixture of both. 



As this sandstone partakes of the schistose quality of the beds 

 which it attends, so it is also somewhat assimilated to them in coloiu-; 

 yet where it begins to predominate over the shale, it lays aside both; 

 growing solid and massive in its structure, and whitish or yellowish 

 white in its colour. This is especially the case in the precipitous cliflfs 

 to the south-east of Cloughton wyke, where, as was said above, the 

 shale is wholly overpowered, and the sandstone becomes independent. 



The second shale being one of the lowest beds of the oolite hills, 

 it may be proper to make a remark or two more, relating to these 

 hills, before we proceed to the next member of the strata. 



At the out-skirts of this range, we often meet with small insu- 

 lated hills, detached from the main body. Hood hill and other 

 appendages to the Hambleton hills have already been noticed. Some 

 hills of the same form, but of a larger size, may be seen at Hawnby, 



