124 Mr. Bryce on the Geological Structure of Roseneath. 



W.N.W. The Gantock rocks are exactly in the line of bearing, but 

 were found to consist of very hard slate. On the opposite coast, however, 

 near Ardgowan, a dike of the same width and direction occurs, which 

 may be the continuation. 



IV. — Coast of Renfrewshire. 



14. The coast section of this county presents only old red sandstone 

 and trap, with occasional beds of limestone. The sandstone rises sea- 

 ward, dipping east and south-east, at a small angle, and everywhere 

 occupies the coast except at Kempoch Point and Cloch Point, where 

 the overlying trap reaches the coast line, and is seen between high and 

 low water, resting upon and altering the sandstone. The great overlying 

 mass of trap sends out innumerable dikes intersecting the sandstone of 

 the coast, and running in very various directions, but with a general ten- 

 dency to the west and north-west. Into a general description of these, 

 and the changes produced by them upon the rocks which they intersect, 

 we cannot enter in this place. One instance only will be given, as bearing 

 upon the subject referred to in Art. 1., in the changes induced upon the 

 limestone at Innerkip. This rock appears in two places near Innerkip ; 

 one bed extends from the bridge on the Greenock road, at the north end 

 of the village, up into the hUl on the south-east of the village, rising 

 with the slope of the sandstone beds, and preserving a thickness through- 

 out, of about 12 feet ; it has been extensively quarried behind the village, 

 but is now little worked. As it is extremely hard, and contains much chert 

 disseminated in veins and bands, the rock is capable of taking a fine 

 polish, and being applied to ornamental purposes; — the colour is dark grey. 

 Between the limestone and the sandstone above it, there is interposed a 

 bed of loose materials, consisting of red sand, spotted with round grey 

 spots, and enclosing pieces of limestone and sandstone. Hence the bed 

 of lime must have been exposed to considei'able decomposition before the 

 sandstone was deposited over it. A lengthened and careful search was 

 not rewarded by the discovery of any fossils. It is however obviously 

 in the position of the cornstones of England. 



Several beds separated by strata of sandstone occur on the shore at 

 the mouth of the river. The whole series is here traversed by dikes 

 of greenstone, the largest of which is about sixty feet wide, and ranges 

 about N.N.W.; the others are so numerous, and so ramified, as almost 

 to defy description. They pierce through the limestone in every direc- 

 tion, thin veins branching from the gi'eater, and often again uniting, 

 while small portions of the limestone and sandstone are entangled in 

 the trap, and traverse it in disconnected veins. The changes produced 

 upon the limestone are of the most interesting kind; I know no 

 locality in the West of Scotland where the posterior origin and intru- 

 sive character of the trap rocks are so clearly manifested, and I 

 would strongly recommend it as a point to be visited by the student 

 of geology. The changes which the limestone has undergone run through 



