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XIX. — On the Distribution of Fossil Remains on the Yorkshire Coast, 

 from the Lower Lias to the Bath Oolite inclusive.* 



By W. C. WILLIAMSON, Esq., 



(curator of the MANCHESTER SOCIETY OF NATURAL HISTORY.) 



[Read May 7, 1834, and November 2, 1836.] 



1 HE formations noticed in the following pages are the lias, the inferior oolite, 

 the lower carboniferous series of Smith, and the Bath or great oolite. 



Lias. 



The lias series on the north-east coast of Yorkshire, occupies a range of lofty 

 cliffs, varying from 100 to 600 feet in height, and extending with little inter- 

 ruption from the Peak Hill, near Robin Hood's Bay, to the village of Saltburn, 

 near Redcar. 



Jt is separable into three great divisions, 1st. the lower lias, 2nd. the marl- 

 stone, and 3rd. the upper lias or alum shale. 



1. Lower Lias. — On no part of the coast is the whole of this division exhi- 

 bited, or has its depth been ascertained. At the base of Rockcliff, near Staithes, 

 it has a considerable thickness, and at Peak Hill, a section of about 300 feet 

 is exposed. It is probable, however, that its vertical dimensions are much 

 greater, as blue clay is brought up by ships' anchors at a considerable distance 

 from the shore ; and as Trochus Anglicus with some other fossils, is found 

 only among the shingle, generally much water-worn, and apparently washed 

 up from submarine strata. 



At present, nothing is known of the fossils contained in those inferior beds. 

 In the exposed portion, the marl, in the lower strata, is compact, arenaceous, 

 and generally of a dull blue colour, whilst in the upper it is more shaly. The 

 fossils are thinly scattered, and few in species. On the scar at Robin Hood's 

 Bay, near the lowest known part, occurs Grijphaa incurva, and a little higher 

 GryphcBa Machullochi, botli in great abundance ; and associated with the latter, 

 is sometimes found Gryphaa depressa. 



A little above this bed is a seam which also contains organic remains, the most 

 common, being Hippopodium ponder osum, Phoiadom.ya amhigua, Pholadomya 



* In this memoir two papers are embodied, one, on the distribution of Lias Fossils, on the York- 

 shire coast, read May 7th, 1834: the other, on the distribution of Oolitic Fossils, read Nov. 2, 1836. 



