﻿Yol. 6 1.] THE BLEA WYKE BEDS IN NORTH-EAST TORESHIRE. 441 



22. The Blea Wyke Beds and the Dogger in North-East York- 

 shire. By Bobert Heron Rastall, B.A., F.G.S., Christ's 

 College, Cambridge. (Bead April 19th, 1905.) 



Contents. 



Page 



I. Introduction 441 



II. The Typical Section : Blea Wy ke Point 442 



III. The Coast-Sections 448 



IV. Inland Sections 453 



V. The North- Western District 455 



VI. Summary and Conclusions 457 



I. Introduction. 



The exact stratigraphical position of the Blea Wyke Beds and their 

 relations to the beds above and below them have given rise to a 

 great deal of discussion, but no very satisfactory conclusion seems to 

 have been reached by any of the writers on the question. 



Many attempts have been made to assign these beds to the Lias 

 or to the Inferior Oolite, but hitherto there has always been some 

 objection to drawing a hard-and-fast line at any particular horizon ; 

 and in these days, when less importance is attached to arbitrary 

 divisions of geological time, and more to broad questions of physical 

 geography, it seems worth while to study the question afresh from 

 a more modern standpoint. 



These beds are also noteworthy for another reason, because a 

 study of them seems to throw some light on the history of the Peak 

 Fault, perhaps the greatest and most important dislocation in North- 

 East Yorkshire. 



Before beginning the detailed study of the Blea Wyke Beds, it 

 will be necessary to say a few words concerning the general structure 

 of the district in which they are developed. 



The southernmost exposure of the Lias on the Yorkshire coast is 

 in the cliffs below what was formerly known as Peak, but now 

 called Ravenscar. 



At this point the beds have a rather steep dip to the south, and 

 by proceeding northwards from Staintondale, we pass in succession 

 over a fine series of Oolitic and Liassic strata. The Oolites form the 

 cliffs as far north as Blea Wyke, a small point and bay almost 

 directly below Ravenscar Bailway-station : here the top of the 

 Upper Lias appears, and can be easily followed in the cliffs for a 

 mile or so to the north-west, where it is cut off by the Peak Fault. 

 This fault has a throw of some 400 feet, and brings up Middle Lias 

 against the base of the Lower Estuarine Series. 



Within this space of a mile are to be seen a set of strata inter- 

 mediate between the Lias and Oolites, such as are known nowhere 

 else in Yorkshire. When we reach the next exposure, less than a 

 mile to the north-west, the character of the section has entirely 



