17 



determine the true horizon of the carboniferous formations on this side. 

 The strata are almost an exact counterpart of those at Ballagan, bufc 

 of greater thickness, and seen in more marked superposition to the old 

 red sandstone which here rises northward, forming the outer part of 

 the Kilpatrick hills. This is the western limit of these beds ; from 

 Ballagan they sink rapidly eastward, their upper portions being 

 seen. in Finglen and Campsie Glen ; beyond which they are overlaid by 

 the sandstone forming the floor of the Campsie valley. About one mile 

 west of Ballagan they are again seen in the bed of a stream above 

 the village of Strathblane ; and still farther north, in Spittal Glen, 

 running up N.W. towards the base of Drumgun hill, they are finely 

 exhibited in several sections, graduating imperceptibly into the beds 

 of the true Old Red. Two great faults here traverse both series, and 

 throw down the Ballagan beds quite out of position. At the head of 

 the glen the latter are directly covered by the basaltic rocks forming 

 the hill tops. The old red sandstone, from this point north wards, is 

 continuous with the great band on the Highland frontier. Through- 

 out the entire district of Lennox, from Dumbarton to Stirling, the 

 geological horizon is greatly obscured by the disturbances attendant 

 on a prodigious outburst of igneous rocks, forming all the higher 

 portions of the hills, and descending in some parts in broad streams 

 into the low country at their base. Such a coulee of basaltic rock 

 crosses the high ground between Strathblane and Milngavie, cutting 

 right through the coal measures, which are tilted up by it on the 

 west part of Craigmaddie Moor, and separating them from the cor- 

 responding measures of the Duntocher district, which reappear in the 

 same relative position as in the Campsie valley, in consequence of an 

 immense fold, or dome-shaped arrangement of the strata. This coulee 

 will be intersected by a tunnel nearly three miles in length on the line 

 of the newGlasgow Water Works. In the neighbourhood of Castlecary, 

 Kilsyth, and Croy, similar outbursts and streams of igneous matter 

 occur, altering the coal strata, and in some places bearing them up 

 with it, so that the seams are worked on the hill tops, and in anticlinal 

 beds along their flanks. An elevatory movement due to this cause, 

 producing an anticlinal axis in the centre of the valley below the 

 " spout," has given to the Ballagan beds their actual position ; at 

 least, it is only by such a supposition that we can explain their 

 situation and their relations to the strata on the south of the valley, 

 or north-west of Craigmaddie Moor. A conical hill of prismatic 

 trap, called Dunglass, above 200 feet high, rises from the centre of 

 the valley, immediately below the section which has been described 



above. 



D 



