366 ARRAN. GEOLOGY. SECONDARY STRATA. 



this irregularity, the solution of these difficulties must 

 be referred to future times. 



I MUST now proceed to examine the secondary strata, 

 as the next in order, commencing with that part of the 

 island where the whole series is visible, as being most 

 explanatory of their history. 



This part of the island comprises the tract which 

 extends from Loch Ransa to Brodick; or, more accu- 

 rately speaking, it terminates on the one side at the 

 point already described as that of the junction of the 

 schist with the secondary strata, while at the other it 

 may be conceived to end near Screeb; beyond which, 

 one bed only of sandstone is continued to a dis- 

 tance that, for the present purposes, may be con- 

 sidered as indefinite. The alternations of the various 

 substances which form this deposit of secondary rock, 

 are nearly all contained within these limits. This tract 

 is perhaps the most interesting part of Arran. All the 

 other phenomena which it offers can be seen in many 

 situations, dispersedly at le*ast, if not connected in one 

 place ; but it rarely happens that so profound and so 

 clear a section of the secondary strata can be obtained, 

 as that which is here displayed. It will be seen, that 

 the interest does not arise merely from the number of 

 substances visible ; since the successions of these might 

 be studied, though with less satisfaction and facility, 

 in many places. Much of it results from the perfect 

 exposure of the continuous edges of the strata, which 

 enables us to study those lateral variations also, of which 

 we seldom meet such clear indications ; while the variety 

 of position which they present in different places, leads 

 to important reflections, respecting the causes and nature 

 of the changes by which this has been produced. 



To describe in detail the succession of these strata, 

 would be to produce a tiresome catalogue, as little inter- 

 esting as the section of a coal field ; while the reader, 



