169 



FAULT REVELATION THROUGH THE AGENCY OF 

 UNDERGROUND WATER, NEAR HAWES, WENS= 

 LEYDALE. 



G. T. McKAY, B.Sc. 

 (plate IX.). 



On the road from Hawes through the Buttertubs Pass to Muker 

 in Swaledale, an interesting section is exposed. It occurs about 

 three miles from the former place, and, as at first seen, seems 

 to be the face of a long disused hme-quarry ; in|fact it was 

 almost passed over as such. But the ' second look ' involved 

 in passing along the top of it (following the road) revealed 

 several peculiar features. Most of these can happily be well 

 seen in the accompanying photograph, and they will be further 

 understood from reference to the diagram. There is a perpen- 

 dicular face of much-weathered limestone, about fifteen feet 

 deep at its centre. This forms the upper side of a narrow 

 cleft, pointed at each end where it comes out to the surface, 

 and widest and deepest in 

 the centre, where the side 

 of this cleft opposite the 

 limestone is broken through 

 by another valley at right 

 angles to and as deep as 

 the original one, and run- 

 ning into the major valley 

 (Foss Dale) on the sloping 

 side of which all this is 

 situate. (Plate IX., fig. 2). 



The configuration thus 

 consists of three small 



valleys. Two of these are in a straight line, opposed to each 

 other, and deepest where they meet ; at which point the third 

 takes off from both, at right angles to them, carrying away 

 the water which runs down them into the major valley below. 



The important feature is that one side (the upper) of the 

 two opposed valleys consists of a vertical wall of limestone, 

 while the other side is more sloping, is for the most part grass 

 grown, and can be seen at one point to consist of black shale. 

 It is through this shale that the third valley has been cut. 



The explanation of these phenomena seems to be that there 

 is a fault running along the side of the main valley, which has 



' M 



1910 Apl. 1. 



Diagram showing position of Exposure. 



