YORKSHIRE NATURALISTS AT ROBIN HOOD's HAY. 241 



the great fault at the Peak. No clear section of this was seen beyond 

 the decided curve of the beds of the Middle Estuarine sandstones, 

 which are thrown, a little further on, against the beds of the Upper 

 Lias. Mr. Hudleston still further indulged the enthusiastic hammer- 

 men by visiting the Crag Hall Quarry, where a notable section was 

 examined and a lucid description given. This quarry is simply a 

 giant excavation left by the alum-workers of former days, when the 

 shales of this coast were valuable, commercially considered. Now, 

 by the rapid development of modern chemistry, the residuals from 

 our gasworks have entirely supplanted this industry of the Yorkshire 

 coast, and hence we see the immense heaps of shale, debris, and 

 calcined material left. And now an arduous ascent was made from 

 the railway, and shortly afterwards, by an unctuous and yet pre- 

 cipitous descent, the Crag Hall Quarry was inspected. 



The Crag Hall section is a very instructive one. Here were 

 shown the Lower Estuarine shales and sandstones resting upon the 

 Dogger series, which again rested upon the alum shales, or 'com- 

 munis ' beds of the Upper Lias. The ' striatulus ' beds, which may 

 fairly be considered as passage beds between the Oolite and the Lias, 

 are wanting in this quarry, and, indeed, the Dogger, which at the 

 other side of the fault attains a thickness of nearly loo ft., including 

 the Yellow and Grey sandrocks, is here attenuated to 4 ft. only. This 

 remarkable difference in the thickness of the strata in such a short 

 distance is a most important geological problem, and must be duly 

 considered. To use the words of the President, ' it can hardly be 

 supposed that, the distance being short, this is due to non-deposition. 

 It really looks as if the bed of the Liassic sea was lifted on the 

 upthrow side of the great fault, and thus brought under the influence 

 of denuding currents, or that the downthrow side sank so as to be 

 preserved from such action. It is a remarkable coincidence that on 

 the westward or upthrow side of the great fault there should be such 

 a disappearance of beds in so short a space. The subject, when 

 more thoroughly investigated, may serve to throw more light upon 

 the changes of level and of other physical conditions which marked 

 the close of the Liassic epoch and the commencement of the 

 Oolitic' The heavy rain now beat more pitilessly than ever, and 

 with extreme reluctance and regret a return had to be made to 

 the station, although if Mr. Hudleston had considered it safe to 

 descend the wet and slippery shales to the shore, the members 

 would loyally have followed him. \c\. enthusiasts, if wise, will 

 always submit to experience and knowledge ; therefore the train 

 for Scarborough was regained. It was certainly a most acute 

 disappointment that, from the violence of the storm, the most 



Aug. 1888. 



