338 



MK. G. BAEEOW ON THE OCCTJEEEK-CE 0? [Aug. IQOI, 



Here the limestone has been exposed by the denuding action of the 

 burn, and is not seen on the higher ground above in the line of 

 strike. The Margie Series forms the floor of the quarry, and the 

 beds are intensely puckered or folded, though careful examination 

 shows that the folds are of no great depth. The peculiarity of 

 this quarry is, that we are able to make out that at the junctions 

 of the different rock-groups the section varies everj'" foot. This 

 is essentially due to a slight south-westerly inclination of the 

 folding, in consequence of which we slowly ascend in the Margie 

 Series as we walk along the floor in the direction of the strike of the 

 folding. The southern wall of the quarry consists of the slaty 

 shale, with the addition of small patches of intensely sheared jasper. 



J'ig. 4. — Diag^'ammatic Section across the Burniesha'ig 

 limestone-quarry. 



S.E. 



N.W 



Old Red 



Jasper Green Rocks Slates etc. AMargie SeriesNHighland 

 ' D \ \ Rocks 



B^ 



This additional variation in the rock next the Margie Series makes 

 the hypothesis of a natural sequence still more improbable. No 

 fault-rock is ])resent, but the shearing at the junction of the two 

 series is intense. Similar phenomena are seen at the northern face 

 of the quarry, where first the shale and then the limestone are in 

 contact with a Highland Grit. The intersection of the two thrusts 

 can be clearly made out at both ends of the quarry, and the cause 

 of the non-appeai*ance of the Margie Series higher up along the 

 hillside, in the direction of the strike, can be easil}' understood. As 

 already stated (p. 337), the type of crushing associated with these 

 thrust-planes does not extend for more than a yard or two into 

 the Highland Grit. 



Thus these little lenticles of the Margie Series, on the north side of 

 the Jasper and Green Rock, lie between a major and a minor thrust- 

 plane. They are confined to the valleys, where alone denudation has 

 succeeded in cutting deep enough to expose their apex. Only in the 

 specially-deep valley of the North Esk is the whole succession of 

 the Margie Series up to the limestone exposed. All along the hill- 

 sides the minor thrust is always cut out by the major, before the 

 former can reach the surface. 



