84 Mr. J. Bryce on the Lignites and Altered Dolomites 



contact with the superincumbent trap." A little way above 

 the limestone quarry, near the ruins of Kelspoke Castle, the 

 beds of sandstone are distinctly seen dipping towards the trap, 

 both the dip and inclination being the same as below the lime- 

 stone ; and it thus appears that the limestone is here, as in 

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

 colemporaneous origin. 



6. The limestone and shale which are interstratified with 

 the sandstone in several places, and at Ascog are also accom- 

 panied by very thin veins of coal, bear a striking resemblance 

 to true coal measures ; and it is therefore 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 the sandstone is the old red, and 

 therefore inferior to the whole coal formation. The reasons 

 lor this opinion may be briefly stated. 



(1.) Since in the adjoining tracts the series of rocks succes- 

 sively 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 con- 

 tinued 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 Gourock, and from Toward 

 Point to Dunoon, and appears again on crossing the Firth, 

 in Dumbartonshire and Stirlingshire, forming the lower por- 

 tions of the Kilpatrick and Campsie hills, and thus constituting 

 a well-marked boundary between the coal basins of Lanark- 

 shire and the primary ranges of the Highlands. (3.) The 

 true coal formation associated with carboniferous limestone 

 exists in Arran, separating distinctly the old red sandstone 

 from the new. This old red sandstone of Arran incloses 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 Devo- 

 nian series of Arran and England. The evidence derived 

 from fossils is unfortunately not applicable, as I was unable 

 to find a trace of any organic substance either in the limestone, 

 sandstone, or shale; and the same statement has been made 

 by Dr. MacCulloch. It is probable, however, that organic 

 remains will yet be found on a more extended and careful 

 search. 



