414 ARRAN. PITCHSTONE. 



occurs in the cliffs between Corygills and ClacMand 

 point ; resembling so strongly a mass of prismatic trap, 

 as to be often overlooked in walking along this shore, 

 even by those who have been directed to the spot. It 

 is accessible from below in one or two points, and 

 the beach is strewed with huge fragments that have 

 fallen from it. From its horizontal position, it has been 

 by some called a bed; but, like trap in similar cases, 

 it may with more propriety be considered a horizontal 

 vein. The visible face is rudely prismatic, and about 

 twelve feet thick; extending for about 200 yards, and 

 terminating abruptly at each end. It is apparently 

 conformable to the sandstone in which it lies ; but 

 whether rigidly so, cannot be discovered, as the faces 

 of the cliff are obscured, both by the mouldering of 

 the rocks, and by dispersed patches of vegetation. Like 

 the sandstone, it inclines to the S. W. in an angle of 

 about thirty degrees. Its texture is tolerably uniform 

 throughout, being most commonly also lamellar, and it is 

 of a dark, or bottle-green colour. It is not accompanied 

 by any visible disturbance of the adjoining sandstone, 

 nor is there any apparent change in either rock at the 

 places of contact ; except that, as happens so frequently 

 among the trap rocks, the vein decomposes to a certain 

 depth near the junction. In the land above these cliffs, 

 not far from Dun Fion, many detached masses are also 

 found ; together with some that appear fixed portions, 

 and may belong to other veins, or may possibly be 

 connected with the large mass now described. 



A better known and more conspicuous vein crosses 

 the road in this place, where it is about thirty feet 

 wide, passing through the sandstone strata. In this 

 example, as in the former, no affection of the sandstone 

 occurs where the two substances unite. The colour of 

 this pitchstone is green and its structure lamellar ; while 

 it occasionally contains a few crystals of felspar so 

 as to acquire a porphyritic aspect. It is tender and 



