﻿Vol. 6 1.] BLEA-WYKE BEDS IX FORTH-EAST YORKSHIRE. 459 



the enormous amount of denudation undergone by the Upper Lias 

 in North-East Yorkshire, especially north-westward of the Peak 

 Fault, previous to, and in part contemporaneous with, the deposition 

 of the Oolites: an instance was given in one of the Author's diagrams. 

 He had himself suggested many years ago that this fault was aline 

 of weakness, which had moved more than once in the history of the 

 district. It was well known that the movement of faults was often 

 secular in character, and that disturbances of the earth's crust were 

 apt to follow old lines. The different developments at the Peak 

 called for some explanation, and if, during deposition, one side of 

 the area was going up while the other side was going down, the 

 existing state of things might have been the consequence. 



He couldnot agree with the Author's description of the Blea-Wyke 

 section, where so large an amount of the Dogger was assigned to 

 the Yellow Sands. There was upwards of 80 feet of rock, con- 

 sisting of an arenaceous and partly-oolitic ironstone of a peculiar 

 chocolate-colour, some of the beds containing a large percentage of 

 metallic iron. The lithology of the Yellow Sands was totally 

 different from this, nor was there anything in the palaeontology of 

 the beds to suggest such an innovation in the reading of the 

 section. Although dissenting in this respect, he thanked the Author 

 for his graphic presentation of the subject. 



Mr. it. S. Herries welcomed a new paper on these interesting 

 beds, and thought that the Author's views were probably, on the 

 whole, correct. It was obvious that the existence of some 170 feet 

 of beds on one side of the fault, which did not occur on the other, 

 w 7 as not a mere accident ; and it was difficult to avoid drawing the 

 inference that there had been a movement along the present fault-line, 

 at a time more or less contemporaneous with the deposition of the 

 Striatul ws-Shales and the Blea-Wyke Beds, as originally suggested 

 by Mr. Hudleston. There were two ways of accounting for the 

 absence of the beds on the north side of the fault — non-deposition 

 and erosion. He (the speaker) was inclined to adopt the latter 

 theory, at any rate in part, as there seemed to be traces of the 

 Sttnatulus-Beds in the junction-sections in places. He instanced 

 especially the beds in the Lofthouse alum- works, and called 

 attention to the occurrence of a Lingula in the Dogger at High 

 "Whitby and Saltwick, and to the existence of a bed of Terebratula 

 trilineata (with numerous other Dogger fossils) between Sandsend 

 and Kettleness. He thought that the problem could best be settled 

 by a careful working-out of the fossils at all the different localities. 



Prof. Watts referred to the importance of this communication, in 

 view of the possibility of a fault moving during the deposition of 

 strata. He suggested that the Blea-Wyke Beds, being of the 

 downthrow type, might be expected to occur elsewhere, and that 

 their absence would prove to be the exceptional, rather than the 

 normal, condition. 



The Author thanked the Fellows for the kindly way in which 

 they had received his paper. In reply to Mr. Fox Strangways, he 

 observed that he had used the term pebbles, for the rounded bodies 



