SECOND SHALE. 8? 



the stratified rocks disappear altogether, their place being occupied 

 by the alluvial cliffs formerly mentioned, in speaking of the celebrated 

 Scarborough spi-ings. The alluvial beds continue till we arrive at the 

 lofty promontory where Scarborough castle rears its venerable head. 

 There, on the east and north sides of the hill, we find a thick bed of 

 shale, which appears to correspond with the Gristhorp shale, while 

 the beds above it correspond with the Filey rocks, or rather with the 

 series of beds at Rowlston scar. 



As the strata at Scarborough castle present an epitome of the 

 contents of the oolite hills,^ it may be proper to notice them more 

 particularly. The following sketch of these strata, as observed on 

 the north and north-east, will be found tolerably correct. 



1. Some beds of whitish or light grey limestone, generally thin. 

 Among these is a portion of the oolite, of a fine grain, the ova being 

 minute. These beds may occupy 20 or 30 feet. 



2. A thick bed of argillo-calcareous sandstone, with large nod- 

 ules of limestone, and cavities filled with yellow marl. This bed, 

 which may be from 6 to 10 feet in thickness, corresponds with the 

 marly sandstone of Rowlston scar, Nawton, &c. Like that, it is 

 hollowed into cavities, and sinuosities, resembling grotto work; as 

 may be seen in the upper part of the castle rocks, fronting the sea 

 eastward. The hard nodules are generally of an oval shape, with 

 their longest diameter parallel to the plane of the strata in Avhich they 

 are imbedded. 



3. Beds of grey limestone, or calcareous sandstone; some of them^ 

 of a texture approaching to crystalline. In the fissures of these beds, 

 and of No. 2, are many beautiful crystals of calc spar. These beds 

 occupy from 15 to 20 feet. 



4. A compact bed of blueish limestone, 6 feet thick, or upwards.. 

 This bed may correspond with the blue and grey limestone of this 

 series; though, as in the instance noticed in describing the Filey 



