202 



Mr. Bryce on the Geology of the Island of Bate. 



as in other parts of the island, subordinate to the sandstone, and of 

 cotemporaneous origin. 



No. 4. 



a, b, sandstone ; c, limestone ; d, trap. 



6. The limestone and shale which are interstratified with the sandstone 

 in several places, and at Ascog are also accompanied by very thin veins of 

 coal, bear a considerable resemblance to true coal measures ; it is there- 

 fore not surprising that coal has been thought to exist in or under this 

 sandstone, and that several attempts have been made to discover it. 

 These, however, have been fruitless, and must always prove so ; since 

 there can be no doubt that this sandstone is the old red, and therefore 

 subjacent to the whole coal formation. Such undertakings should never 

 be entered upon without the sanction of a geologist or scientific miner. 

 As the matter is one of some importance economically, I shall briefly 

 state the reasons which have led me to this conclusion. 



(1.) Since in the adjoining tracts the series of rocks, successively 

 superimposed on the central granite, is complete, and old red sandstone 

 occupies in these its proper place, we may fairly infer that the sandstone, 

 which in Bute succeeds the slate series, must be the old red. (2.) This 

 sandstone, if continued out on the line of its bearing, would coalesce with 

 that which forms the Cumbrays, and with that which, rising to the west 

 from beneath the great mineral basin of Ayrshire, skirts the coast from 

 Ardrossan to G-ourock, and from Toward Point to Dunoon, and appears 

 again, on crossing the firth, in Dumbartonshire and Stirlingshire, forming 

 the lower portions of the Kilpatrick and Campsie hills, — and thus consti- 

 tuting a well marked boundary between the coal basins of Lanarkshire 

 and the primary ranges of the Highlands. (3.) The true coal formation, 

 associated with carboniferous limestone, exists in Arran, separating dis- 

 tinctly the old red sandstone from the new. This old red sandstone of 

 Arran encloses beds of limestone which are similar to those of Bute, and 

 contain the same fossils as those limestones termed cornstones, which in 

 England are subordinate to the old red system. Thus the red sandstone 

 of Bute seems to be identified with the old red series of Arran and Eng- 

 land. The evidence drawn from fossils is unfortunately not applicable ; 

 as I was unable to find a trace of any organic body, either in the lime- 

 stone, sandstone, or shale, and the same statement has been made by Dr. 

 MacCulloch. I have no doubt, however, that organic remains will yet be 

 found, on a more extended and careful search. 



7. The extent of the trap at Ascog has been already hinted at, (Art. 



