The Geology of this Part of the West of Scotland presents many interesting features. A sandstone, similar to the red sandstone of Warwickshire in appearance, but considered by some geologists an older formation, called the old red sandstone, constitutes the foundation of the town of Dumfries, and supplies abundance of excellent material for the new building's of that town, which display it to advantage in handsome fronts of squared and frequently polished blocks, which in the better class of buildings, are very neatly jointed with glazier's putty. The same rock continues to the foot of the hills, which, within a few miles of Dumfries, commence with argillaceous schistus, trap, basalt, and granite, and continue, with freestone and secondary limestone intervening here and there, over all the tract which we have mentioned, to Paisley. Advancing up the shores of the Clyde, we saw from the road, at low water, a lower stratum of dark basaltic rock, which is intimately associated with the red sandstone above, appearing to pass by gradation into it. The intervening strata of sandstone seem as if partially fused by proximity to the basaltic rock beneath. The strata in a descending series are:- I. Red sandstone, a fine conglomerate; 2. Grey siliceous fine-grained sandstone, with particles of green earth; 3. Striped red and grey sandstone, similar in composition to No. 2.; 4. More compact sandstone, with numerous particles of felspar, presenting the appearance of having been indurated by proximity to the basaltic rock; 5. A rock which seems intermediate between sandstone and trap; 6. A black basaltic rock, the lower part intersected by vertical fissures. We collected specimens of all the above from a bed, not more than a yard in thickness, situated on the shore at Largs. The first large mass of granite which we saw was the Criffel mountain, near Dalbeattie; and the first limestone was at Closeburn, where it is most scientifically worked by Mr. Stuart Menteath. (See Vol. II. p. 107. 402.) This rock again occurs at Straiton; and, from Girvan along the coast as far as Saltcoats, limestone and coal are in the greatest abundance, and are extensively worked, both for home consumption and for exportation. Both limestone and coal occur again in the neighbourhood of Paisley, where they are also worked to a great extent.
