Vol. 62.] ANNIVERSARY ADDRESS OF THE PRESIDENT. iXXVii 



was torn away from the other along these tear-belts. Evidence of 

 this action is given in my ' azotes,' in the case of the well-marked 

 faults which affect the Coniston Limestone between Windermere 

 and Coniston Lakes ; but perhaps the most striking proof of the 

 existence of these ' tears ' is furnished by the outcrop of the 

 Armboth dyke between Borrowdale and Thirlmere. This dyke is 

 seen to be vertical on Fisher Crag. A tear-fault runs along Fisher- 

 Gill which shifts the dyke for nearly a quarter of a mile to the 

 north-east, and a similar shift is caused by another tear along 

 Middlestead Gill. 



With such a movement as that above noticed a simple straight 

 cut is unlikely to occur ; the action really is more akin to a tearing 

 of the rocks, and accordingly the tear-faults are usually belts of 

 much broken rock. 



In my paper on 'The Waterways of English Lakeland,' 1 I 

 described in detail one of these belts in Troutbeck, which, as the 

 result of detailed mapping of the zones of the Stockdale Shales, was 

 found to be occupied by a series of faults of different sizes cutting 

 the rocks into blocks so as to form a gigantic fault-breccia. Of such 

 a belt of broken rock, produced by horizontal, or nearly horizontal, 

 movement in a more or less vertical plane, I propose to speak for 

 convenience as a ' shatter-belt.' Although many of these shatter- 

 belts occur along the lines of ' tear-faults,' it must not be supposed 

 that permanent displacement of the rocks at the sides accompanies 

 all or even the majority of the belts. Many of them show no signs 

 of faulting, and were probably produced by temporary movement, 

 which, on its cessation, left the rocks in their original positions. 

 I propose to discuss later the importance of these shatter-belts in 

 producing modifications of the surface-features. At present, I confine 

 myself to an account of their characters and general distribution. 



In the paper referred to above I suggested that the ' cleft of 

 Dunmail Raise and the valleys of Thirlmere and Grasmere, which 

 run north and south from that cleft, are apparently due to a belt of 

 shattered rock,' 2 and stated that I was led to believe that many 

 of the minor valleys of the volcanic tract of the Borrowdale Series 

 had been formed along similar belts, and not along simple fractures. 

 Since this paper was written I have paid more attention to these 

 belts, and find it easy to recognize them in the volcanic tract, 

 where they are very abundant and of varying width and length. 



1 Geogr. Journ. vol. vii (1896) p. 602. 



2 Op. cit. p. 612. 



