70 



at the march of Achab farm, at Glen Laodh on the hill side south of 

 the road from Brodick to Shiskin nearly opposite Moniquail farm, 

 in Clachan glen, and a few other places. They are without fossils, 

 and similar to the cornstones already noticed in Arts. 27, 28, 35, 38. 

 We shall again refer to them in our separate " Excursions." 



48. The southern half of the island, southward of the old red 

 sandstone boundary above denned, that is, from the String road and 

 valley of Mauchrie water to the South End, is composed of several 

 members of the carboniferous series, broken through and overlaid by 

 various igneous rocks, chiefly those of the greenstone type. The 

 prevailing rock and substratum of the whole southern plateau is red 

 sandstone, varying from a fine compact structure to that of a coarse 

 conglomerate. A narrow band of this sandstone extends also along 

 the eastern shore northwards to Corrie ; and again from the Fallen 

 Rocks north-west to the Scriden at the northern extremity near the 

 entrance of Loch Ranza. Subordinate to this sandstone are beds of 

 limestone, abounding in fossils of true carboniferous types, beds of 

 shale and coal, in which are found fossil plants and shells, such as 

 characterize these strata in the basin of the Clyde. The structure 

 indeed is quite analogous to that of the Clyde basin, the peculiarities 

 of which have been already explained in Art. 24. The limestone 

 does not occur at the base of the system, nor does it occupy any 

 determinate place in it, but is found throughout the whole series of 

 beds in repeated alternations with the sandstone and shales. These 

 alternations are seen in section on the sea shore along the east border, 

 on the hill side between Corrie and Brodick, along the high grounds 

 on both sides of Glen Cloy, in Clachan glen, Glen Scorodale, and 

 other water channels issuing westward ; and in the Alaster water 

 above Lamlash, they descend almost to the bottom of the glen, 

 where alluvial deposits obscure the old rocks. On this ground we 

 refer the whole of the strata of the southern division of the island to 

 the carboniferous series. The alternations in question are not seen, 

 it is true, on the Corriegills, Whiting bay, or Kildonan shores, nor 

 do they appear among the sandstones of the South End ; but such 

 massive strata of red sandstone as appear along the east and south 

 shores, are common in the carboniferous system, and form indeed 

 everywhere its prevailing member. They are conformable to the 

 strata inland, in perfect sequence with them, of the same mineral 

 structure, and without any fossils of New-Red types. We do not 

 therefore hesitate to refer them all to the carboniferous system ; and 

 we are persuaded that the distinguished geologists who established 

 such a classification for Arran, will be the first to agree in this view. 



