LIAS CLIFFS. 93 



shale. These interposed strata are identical in geological characters with 

 the marlstone of Lincolnshire, Rutland, and the midland counties. In 

 all these counties the marlstone is wonderfully prolific in fossils : and we 

 shall find in the sequel that it is equally productive in the Yorkshire cliffs. 

 At the Peak, about forty feet of this series appear, and yield abundance 

 of terebratulae, dentalia, aviculae, &c. Below these sandy beds is an im- 

 mense escarpment of more than three hundred feet, composed of the 

 deeper lias shale, with many layers of ironstone, resting upon more solid 

 floors of the same strata. In these solid beds, the lowest probably which 

 are exposed on the whole coast, we find the gryphsea incurva, which 

 so generally accompanies the inferior beds of lias in the south of 

 England. 



Henceforward to the town of Robin Hood's Bay, the cliffs are com- 

 posed of the deeper lias shale, in nearly level layers, surmounted by a 

 variable covering of diluvial clay and pebbles. At low-water, the ranges 

 of the strata are seen in grand curves sweeping across the whole extent 

 of the bay. Beyond Baytown, the cliffs increase in altitude, and a rapid 

 declination of the strata towards the north is observed for the space of 

 three miles. In consequence of this the deep shale sinks into the sea at 

 little more than a mile from Baytown ; the marlstone beds have all 

 disappeared in about two miles, and from thence to Whitby the shore is 

 kept by the upper lias shale. So great is the depression, that between 

 Hawsker bottoms and the place called High Whitby the carbonaceous 

 sandstones above the lias stoop very nearly to the water. The solid beds 

 of sub-calcareous sandstone and ironstone (which constitute the marlstone 

 series) form prominent scars, where they sink into the sea, and their 

 blocks, which are scattered at the foot of the cliffs, may be advanta- 

 geously examined for fossils. The highest point of the coast between Bay- 

 town and High Whitby, (two hundred and seventy-five feet,) is marked 

 by the termination of the dogger series. This irony sandstone, though 

 at Blue Wick on the south of Robin Hood's Bay it is so rich in fossils, 

 does not here contain a single shell, and is very thm ; but the sandstones 

 which succeed above contain the same plants as at the Peak. To 



