THE PLOVERFIELD GRANITE. 



17 



TJie Ploverfield Granite. 



11. The Ploverfield granite 

 occurs amid strata which un- 

 doubtedly belong to the carbon- 

 iferous' system. The tract is 

 situated on the west side of 

 Glen Cloy, and that branch of 

 it called Glen Dhu. The hills 

 here are the highest portion of a 

 long ridge running up south- 

 west from the plain of Brodick, 

 and dividing Glen Cloy from 

 Glen Shirag. At the origin of 

 this ridge are beds of carbon- 

 iferous limestone with fossils, 

 under the north wall of the 

 enclosure of Brodick Church. 

 On the upper slope of the ridge 

 beds of limestone and shale 

 also occur in the sandstone, not 

 far from the north base of the 

 Windmill Hill a high, elon- 

 gated, narrow ridge, steeply 

 overhanging Glen Dhu, and 

 composed of quartziferous por- 

 phyry. On its south-west base 

 the granite first appears, sepa- 

 rated, in some places at least, 

 from the porphyry by a narrow 

 band of altered sandstone. 

 Thence, keeping at a high 

 level, it extends along the 

 hill slopes at the head of Glen 

 Dhu, and terminates southwards 

 against a ledge or low cliff' 



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