GEOLOGY OF ARRAN. 



1. THE Island of Arran is twenty miles and a half long from 

 N.N.W. to S.S.E. ; ten and a half miles broad, and with 

 Holy Isle and Pladda includes an area of 103,953 acres. 

 The number of rock formations, sedimentary and plutonic, 

 which are found within this limited space is truly remarkable, 

 perhaps unparalleled in any tract of like extent on the surface 

 of the globe; while the varied phenomena which they present 

 in their mutual contacts and general relations to one another 

 are of the highest import in theoretical geology. The variety 

 indeed is so great, and the interest so lively and pleasing, 

 which an examination of the structure of the island and its 

 charming scenery excite, that, as Professor Phillips has re- 

 marked, every geologist who visits Arran is tempted to write 

 about it, and finds something to add to what has been already 

 put-on record. For the student there cannot be a finer field; 

 the primary azoic rocks, the metamorphic slates, the lower 

 palaeozoic strata, the newer erupted rocks, and phenomena of 

 glacial action, may all be examined by him in easy excursions 

 of a few days; and the exposition of the strata is so complete 

 in the rugged mountains, deep precipitous glens, and unbroken 

 sea coast sections, that the island may truly be called a grand 

 museum, arranged for his instruction by the hand of Nature. 



Physical Features. 



2. A line running from the north angle of Brodick Bay, 

 almost due west to lorsa water-foot, divides the island into 

 two nearly equal poi-tions, strikingly different in their geolo- 

 gical structure and in their outward features. The northern 



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