236 Mr. Williamson on the Fossil Remains in Yorkshire. 



With but few exceptions, these plants are all characteristic of the shales in 

 which they are found. The following species also occur in the lower sand- 

 stone and shale. 



Pecopteris Williamsonis. t Taeniopteris vittata. 



Neuropteris ligata. Solenites Murrayana. 



Sphenopteris stipata. I Lycopodites Williamsonis. 



In the same seam I have found Cypris concentrica, Unio distortus, (Bean) 

 and another undescribed species of Unio. This fact, combined with the ab- 

 sence of marine remains, would seem to indicate that the origin of these 

 sandstones and shales is lacustrine, a fact of which I have little doubt. If this 

 be correct, it would appear that a considerable time must have elapsed between 

 the deposition of the marine fossiliferous divisions forming the top of the Bath 

 oolite and the hard ironshot seam of Crinoideae, upon which the sandstone? 

 and shales rest. 



The fossils characteristic of the oolitic seams of the great oolite are few, as 

 they bear a general resemblance to those of the cornbrash and inferior oolite. 



The long tuberculated spines of a Cidaris have not been met with in this 

 neighbourhood in any other rock. Professor Phillips has pointed out Phola- 

 domya acuticostata and Rostellaria composita as characteristic of the stratum, 



found in any other. 



Ammonites Blagdeni. 

 Belemnites Aalensis. 

 Phasianella cincta. 



Terebratula spinosa. 

 Large spines of a Cidaris. 



To these may be added the mass of gigantic saurian bones from the layer 

 of ironstone. 



The Bath oolite on the Yorkshire coast is not extensively used as a build- 

 ing-stone, but the lower part of it, and the hard crinoidal bed at Gristhorpe 

 Bay and Ewe Nab, have been very successfully employed in erecting the 

 piers at Scarborough. These beds are remarkably durable, and are conse- 

 quently well calculated for strong water-works, where no particular smooth- 

 ness is requisite. The attempt has been made to procure lime from some of 

 the beds, but with so little success as to check further trials, especially in a 

 country where a superior material is abundant. 



