Vol. 57.] ["siLrfilAN [?] ROCKS IX FORFAKSHIRE, ETC. 



lower part of the Margie Grits is absent, and so too the whole of 

 the underlying Jasper and Green-Eoek Series. In view of the 

 intense shearing of the rocks at the fall, it is probable that the 

 Highland rocks are driven over the Margie Grits by means of a 

 reversed fault. 



Two points are especially well shown here. First, it is impossible 

 to locate the exact junction of the two series ; secondh', the crushing 

 accompanying this movement extends only for a yard or two into 

 the Highland Grits. 



(4) The Clattering Bridge Quarry (fig. 3). — Regarding 

 the section in this quarry, it may be sufficient to state that, as 

 in the Crichie Burn, the upper beds of the Margie Series are in 

 contact with the Highland Series on the north side, and with the 

 slaty shale and jasper on the south. Neither can be a natural 

 junction, and there is no ordinary fault-rock present. The junction 

 in both cases is marked by intense shearing, and both are probably 

 thrust-planes. But we here see clearly for the first time that these 

 two planes intersect at the top of the western end of the quarry, and 

 that the more northerly plane cuts out the more southerly. The 

 displacement along the margin of the Highland Series has been 



Fig. 3. — Dkigrammaiic Section across the Clattering Bridge 



limestone-quarry. 



S.E. N.w 





Highland 

 Series 



0]d Red 



.FAULT 



"'ilfcr^iliiiiliP 



Jasper, Green Rocks, etc. ^\ Margie Series B 



SB - JASPER 



produced by a major thrust, and that between the Margie Series 

 and the Jasper, etc., by a minor thrust. The effect of the inter- 

 section of these two thrust-planes is that, on the slightly higher 

 ground to the south-west, there is no outcrop of the Margie Series. 

 It is only because the burn here has cut through the point of inter- 

 section of the two thrusts, that the wedge-shaped mass of the Margie 

 Series contained between them is exposed. This is made perfectly 

 clear in fig. 3, above. Further, we now begin to see the meaning 

 of the fact that these quarries all lie in valleys ; for in the valleys 

 alone has denudation cut deep enough to expose the rocks betweeu 

 the two thrust-planes. 



(5) The Burnieshaig Quarry (fig. 4, p. 338).— This old 

 quarry, in the Margie Limestone, lies about a mile almost due 

 north of Drumtochty Castle, and a small burn flows through it. 



