ARRAN. GEOLOGY. SECONDARY STRATA. 379 



powerful to expose the subjacent rock, producing the 

 same unsurmountable obstacles in these as in the valley 

 beneath.* 



In returning from Glen Sannox along the shore, for 

 the purpose of continuing the observations on the sand- 

 stone, no remarkable appearances occur till we arrive at 

 Corry; the strata continuing also to present the same dip 

 which prevails from Scriden southwards. Near that vil- 

 lage, the white sandstone is followed by an alternation 

 of strata similar to those already described on the northern 

 side of Scriden, but more limited in extent, and far short 

 of them in variety as well as in number. The red and the 

 white sandstone, as well as the 'limestone, have here been 

 quarried for economical purposes, and these quarries hav- 

 ing been long wrought to a considerable extent, great 

 facility is afforded for examining the order of the strata. 

 They are not however so distinct or decided as to render 

 it necessary to describe them very minutely. The beds of 

 limestone which form the lower and most conspicuous 

 portion, are numerous, and divided by thinner beds of 

 coloured shales, similar to those which occur towards the 

 north, and often abounding in oxide of iron. These are 

 followed by thicker beds of schistose clay, or marie, vari- 

 ously coloured, and often much mixed with calcareous 

 earth ; to which succeed alternations of highly argilla- 

 ceous sandstone, and of the same marly shales ; the series 

 terminating finally in a whitish sandstone. The characters 



* To pursue this investigation it would be proper to commence either 

 at Screed (formerly described) or in Glen Sannox, tracing the boundaries 

 of the granite and the sandstone carefully along the whole line, between 

 the two. If the schist disappears from the hill after leaving Screed, the 

 geologist will naturally increase his diligence, and may possibly under 

 favourable circumstances determine a point which I am compelled to 

 leave in doubt, having hitherto been always impeded by the unfavourable 

 state of the weather. In the accompanying map I have, as before 

 remarked, traced the line in question by a white space between the 

 granite and sandstone; and that line will point out the direction to be 

 taken by those who may be inclined to enter on this task. 



