116 DESCRIPTION OF THE STRATA. 



out. The ordei- is of course reversed, where the sandstone passes 

 into shale. Not unfrequently, where beds of shale and sandstone 

 alternate, we find a bed of shale enlarging its dimensions, so as to 

 encroach on the sandstone above or below, which is hence reduced 

 to a thin seam, if not thrust out altogether: or vice versa, a seam or 

 small stratum of sandstone may be seen swelling into a vast bed, 

 compressing the shale above or below it into a small compass, or 

 entirely excluding it. Instances of such transitions may be seen in 

 abundance along the coast, as in the cliffs between Whitby and Up- 

 gang, and especially at Hawsker Bottoms, and the cliffs opposite 

 Gnipe-houe. In the latter place, the sandstone a little above the 

 alum rock suddenly acquires an immense thickness, forming a mas- 

 sive bed about 40 or 50 feet thick ; but this bed continues only for a 

 «hort space, being again subdivided into thinner beds, interstratified 

 Avith shale. Remarkable transitions may also be observed in the beds 

 that form the cover of some of the alum-works, particularly those of 

 Stoupe Brow and Lofthouse. 



Though the shale of this series is generally either sandy and 

 micaceous, or bituminous, or a mixture of both, yet in several in- 

 stances it contains a large proportion of clay. This is the case with 

 a bed of shale at the tipper end of Tripsdale, a branch of Bilsdale. 

 It has a dark brown colour, and a soapy feel ; and is easily divided 

 into thin plates, which in their recent state are soft and elastic, but 

 when prepared by being roasted in hot turf ashes, are used by the 

 inhabitants of the neighbouring vales for baking cakes, being capable 

 of bearing the heat of a common fire for several years. From the 

 use to which these plates are applied, the ravine where they are ob- 

 tained is called Bakestone-gill. 



The shales of this member of the strata contain very few animal 

 remains, but in the bituminous shale above the coal seams, we find 

 abundance of vegetable impressions. 



