1855.] 



NICOL GRAMPIANS. 



547 



porphyry {p) is quarried, and a si- 

 milar bed is seen on the coast near 

 Cove. At this village also a large 

 mass of granite {g) is quarried. 

 As we approach Aberdeen, granite- 

 veins become more and more nu- 

 merous, until near Girdleness, im- 

 mediately south of the Dee, they 

 almost form the predominant rock. 

 The most remarkable points in 

 this section are, — the position of 

 the clayslate and mica-slate, and 

 the relation of the metamorphic 

 strata to the Old Red Sandstone. 

 In regard to the former, the clay- 

 slate, usually considered as the 

 newer, and undoubtedly the less 

 altered, rock, appears to dip under 

 the older mica-slate. My impres- 

 sion is, that this is truly the case, 

 and that, in proceeding along the 

 coast, there is an ascending series 

 from the less metamorphic to the 

 more metamorphic rock. But this 

 could not be the original position 

 of the masses ; and I can only 

 explain the phsenomenon by sup- 

 posing that a complete inversion of 

 the beds on the southern margin 

 of the chain has taken place. In 

 the north they regain their ori- 

 ginal position, dipping away from 

 the great granitic axis, or rather 

 foundation, of the country. The 

 change of inclination also seems to 

 be effected in a peculiar manner by 

 the highly convoluted mica-slate 

 and gneiss strata folding up, as 

 it were, on themselves, and thus 

 pushing out the upper and exterior 

 beds, as if by great intruded wedges 

 of rock. It is thus an instance in 

 our own country of the fan-shaped 

 stratification so often noticed in 

 the Alps. 



How far this inversion extends 

 along the border of the mountains 

 has not been determined. Near 

 the western termination of the for- 

 mations, as well seen along the 

 Gare Loch on the Firth of Clyde, 



i<5 



o 



*0 (1) 



o 



CM 



O 



a 



So <V 

 "I ^ 



§ J 



"to 

 so 



So 

 «C 



so 



So 



2c 



•J3Al}I UOd 



•uaapjaqv 



•J3Aia 33CI 



•asnotimSiq 



SS3U9lpil9 



•3A0Q 





•;U10J UOJJBQ 



•uaA«iiauo:)S 



i;3'TS 



-> So 



k£ 



