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PEOCEEDINGS OF THE GEOLOGICAL SOCIETY. 



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been called gneiss, and has 

 not as yet been distinguish- 

 ed from the older gneiss on 

 any map, though the two 

 are separated by vast for- 

 mations of Cambrian and 

 Lower Silurian age. (Com- 

 pare this order with that of 

 the maps of Macculloch and 

 Cunningham f.) 



It is, however, well ex- 

 posed, as forming the low 

 maritime headlands of Su- 

 therland and Ross. This 

 old gneiss is here and there 

 traceable to Cape Wrath 

 and the western side of 

 Loch EriboU. It is also re- 

 presented in the woodcut, 

 fig. 1, as lying beneath Cam- 

 brian red sandstone and 

 conglomerate. The same 

 order extends southwards 

 along the west coast of Ross- 

 shire J. The prevalent strike 

 of this old gneiss is E.N.E.- 

 W.S.W., the strata being 

 variously inclined at high 

 angles, and highly contort- 

 ed. The body of the rock, 

 being usually hornblendic, 

 is also often penetrated by 

 powerful granitic veins. 

 This older and massive 

 gneiss, usually of darker 

 grey colours and of greater 

 specific gravity than the 

 younger rock hereafter to 

 be described, is seen to 

 subside to the east be- 

 neath the overlying forma- 

 tions, whether they consist 

 of red conglomerate and 

 sandstone, near the West 

 Coast, or of quartz-rocks 

 with limestone and mica- 

 schists that appear at a short 



t Transactions of the High- 

 land Agricultural Society, vol. for 

 1839. 



\ See Nicol, Quart. Journ. 

 Geol. Soc. vol. xiii. p. 19, 



