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Kocks on the north-east coast, and occupies the shore thence to the 

 inarch of Achab farm, half a mile north of Corrie. Here it retires 

 inland, the carboniferous formations taking its place on the shore ; 

 is interrupted for a short space, south of Corrie, the newer sandstone 

 then resting on the slate; is again resumed on the west base of 

 Maoldon, and stretches thence continuously westward, around the 

 border of the slate to the mouth of Mauchrie water. Between this 

 point and Dugarry, near lorsa waterfoot, it attains its greatest 

 breadth. The breadth is also considerable from the Fallen Rocks to 

 a point a little south of the base of Ciod-na-Oich. A line from the 

 north side of Brodick bay to Dugarry very nearly marks out its line 

 of junction with the slate. The structure varies from a fine grained 

 red sandstone to a coarse conglomerate or pudding-stone, in which 

 the fragments are more than a foot in diameter. The coarse and 

 fine strata do not follow any particular order, but alternate through- 

 out the formation, indicating the operation of powerful currents, and 

 intermediate periods of repose. The imbedded fragments in the con- 

 glomerate are mica slate from a distant source, the ordinary slate 

 adjoining, and quartz of two varieties, of which one is the common 

 white quartz, forming veins in the slate, and the other a peculiar 

 resinous quartz, of a cinnamon colour, not found in Arran, and of 

 which we know no locality. This latter is rounder and polished, 

 while the other is often angular or slightly rounded. The resinous 

 variety is exactly the same as fragments which occur abundantly 

 and of large size in the conglomerates of the east coast of Antrim, 

 but not found in situ anywhere in the north of Ireland. It is diffi- 

 cult to account for the appearance of these in the conglomerates ; 

 they may have some distant source among the Grampians. It is 

 remarkable that fragments of granite do not occur in the conglome- 

 rate ; none of the Arran sandstones have as yet yielded a piece of this 

 rock to any observer. The conclusion to be drawn manifestly is 

 that when these sandstones and conglomerates were in process of 

 formation by the wearing down of the slate rocks and the transport 

 of the fragments by water, the granite of the interior was not exposed 

 to disintegrating causes, but remained as yet in hypogene depths, pro- 

 tected most probably by the enveloping slate rocks. Facts to be 

 stated farther on will throw light on this curious subject. It may 

 here be merely noticed, that the sandstones of the coast have the 

 edges of the strata turned up towards the central granite, and that 

 north of the mouth of North Sannox water, the dip is towards the 

 north-east and north, while south of this point it is south-east and 

 south. Beds of limestone occur subordinate to the old red sandstone, 



