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among the strata, and elevation to the day, date back to an earlier 

 period ? The close proximity of the Craig-Dhu granite to the border 

 of the carboniferous formations, if it be not actually enclosed in these, 

 evidently points to an identity of age with that of Ploverfield, and 

 renders their simultaneous eruption extremely probable. How then 

 is the Goatfell granite related to the old red and carboniferous for- 

 mations ? It has been long established, and is well known that it 

 everywhere throws powerful veins into the encircling slate-band 

 around the borders of the northern district, greatly altering the slate 

 along the line of junction, and disturbing its stratification. The slate 

 is manifestly heaved up by it ; and in some vertical sections, as at 

 Tormidneon, and the hill sides north of Glen Catacol, we have slate 

 above and granite below, with numerous alternations where the two 

 rocks approach. The granite was, therefore, injected in a molten state 

 amid the already formed strata of slate. But, further, it was sug- 

 gested long ago by Murchison and Sedgwick, in their celebrated 

 paper on Arran (Geol. Trans., vol. in., second series, 1835), that the 

 bed of limestone on the north point of Maoldon may have once been 

 continuous with the Corrie stratum, and that its actual position is 

 due to an upthrow by a protruding mass of granite advancing from 

 the central mass east of Goatfell. If this be admitted, it would make 

 the intrusion of the granite posterior to the deposition of the car- 

 boniferous formations, and so render probable an identity of age 

 between the Ploverfield granite and that of Goatfell. We think, 

 however, that this view is liable to question ; we often find exactly 

 similar bands of limestone amid the strata of coal sandstone, without 

 any evidence of former continuity, or such cause of disturbance; 

 and the amount of vertical displacement implied in the supposition 

 could hardly have taken place here without a fracture of the 

 crust, and the appearance of granite on the surface, so narrow is 

 the band of sedimentary strata superimposed upon the granite. A 

 positive conclusion, then, seems scarcely justifiable from -this case. 

 A stronger presumption is derived from the high angle generally 

 assumed by the sandstones, when they approach nearest the granite, 

 on account of the narrowness of the slate band along the Corrie dis- 

 trict. An extremely interesting junction in the Sannox burn throws 

 an unexpected light upon this question of relative age. A few hun- 

 dred yards above the Barytes mill a narrow band of slate crosses the 

 river at right angles, between the granite on one side, and the old 

 red sandstone on the other. The slate is very much altered by the 

 close proximity of the granite ; it has, in fact, the structure and aspect 

 of Lydian stone or basalt ; and the sandstone also has a highly meta- 



