ROCKCLIFF. 101 



on little pedicles of shale. They have evidently protected the shale 

 beneath them from wasting. 



The sandy conchiferous marlstone beds, which in Colborn nab 

 cover the lower lias shale, are seen rising with it, and contributing to 

 swell the altitude of Boulby and Rockcliff. The lower part of this series 

 is generally the most solid, and projects in broad compact floors above 

 the lias. On the surfaces of such beds lie innumerable multitudes of 

 oysters, dentalia, pectens, cardium truncatum, avicula inaequivalvis, 

 and, more rarely, about Staithes, * beautiful fossil star-fishes of the genus 

 ophiura. The marlstone may be well examined on the shore from the 

 boiling-houses of the Rockcliff works to Skinningrave, for there the 

 beds come near to the level of the sea. But along the whole coast fallen 

 masses of this rock abound, and will richly reward the researches of the 

 industrious collector. Above lie the ironstone courses which were noticed 

 on the side of Staithes harbour. These range uninterruptedly across the 

 front of Boulby and Rockcliff, and again shew themselves in the highest 

 part of Huntcliff. Still higher in Boulby and Rockcliff, we trace the 

 soft shales and hard shales with limestone nodules, which were observed 

 at Kettleness and near Staithes ; on these lies the great bed of aluminous 

 shale, which is so extensively worked, and the whole is surmounted by 

 the sandstone cap rock. 



In Boulby cliffs, then, we have the whole series of lias beds exposed, 

 and are thus enabled to groupe the minuter parts of the formation into 

 convenient natural divisions, and to apply these to complete other less 

 perfect sections. 



The statement in the following page, referring by figures and letters 

 to the general and enlarged section, presents a summary view of the 

 whole lias formation visible in the northern cliffs. 



* Mr. Miller, of Bristol, informs me that fossil specimens of ophiura have been found in the 

 lias at Fretherne, in Gloucestershire. 



