from whom it was lately purchased by the Duke of Hamilton." 

 (New Stat. Acct., "Bute," p. 55, 1840). 



WHITING BAT. The sandstone of the shore is traversed here by 

 numerous dikes, and strewed with granite boulders of the coarse 

 variety, of which one is larger than any south of Brodick, with the 

 exception of the great Corriegills boulder. The relation of the trap 

 and sandstone are finely exhibited in Glen Eisdale. At the head of 

 this glen is the finest waterfall in the island ; on the brow of the 

 hill west of the fall, and near the side of the cart-road, we noticed, 

 upon slabs of greenstone, some well marked glacial striae, directed 

 nearly east and west. At King's Cross point there is a broad 

 bed of columnar basalt in the sandstone, the heads of the columns 

 forming a pavement upon the shore. Between Lamlash and Clach- 

 land point there are numerous dikes, some of which stand out more 

 boldly from the terraced surface of the old sea-beach than any dikes 

 in Arran. 



MOKEADH-MHOB GLEN. At the opening of this glen, in the bed 

 and banks of the stream, and of the lead of water connected with the 

 large mill adjoining, there are two great beds of pitchstone. They 

 are finely exposed, and exhibit very strikingly those transitional 

 phenomena already alluded to as marking the relations of this rock 

 to hornstone and claystone. 



Associated with the pitchstones there are claystones, hornstones, 

 quartz rock, and porcellanite. Hornstone, that is, chalcedonic or 

 jaspery chert, seems to be the link between pitchstone and claystone. 

 Hornstone and pitchstone are both almost entirely siliceous ; the 

 difference consisting in the colour and degree of toughness arising 

 from a slight change in composition, or variation in the rate at 

 which they cooled, or from both. By this change pitchstone passes 

 into hornstone. In this hornstone a great many light-coloured 

 spots with dark centres are gradually developed; and bands of this 

 variety succeed the common hornstone. Next to this there follows 

 a hard quartzose claystone, and the series terminates in the common 

 claystone of open texture, like that of the Corriegills shore already 

 described. The spots or specks are minute spheres, most probably 

 of felspar or quartz, or of both, and have probably originated in the 

 manner suggested at the end of Art. 75. They present a close 

 analogy with the spherulitic claystone of Corriegills; but the 

 radiated structure of the latter does not exist here. Even the 

 larger spherules of the pisolitic hornstones do not exhibit this 

 structure. The quartz rock at the upper end of the higher pitch- 



