Summer Excursions, 1872

Abstract

April 20.—Maryhill and Possil. Striated Rock-Surfaces and Boulder Clay. May 4.—Giffnock. Sandstone Quarries. May 18.—Corrieburn. Lower Carboniferous Beds. May 24.—Craignethan. Sections of Lower Carboniferous Sandstones and Shales. June 1.—Beith. Carboniferous Limestones. June 8.—Possil. Striated Rock-Surface and Boulder Clay. June 15.—Milngavie and Craigmaddie. Zeolitic Trap, &c. The following notes refer to one of the excursions to Possil:— The object of our visit lay quite in the neighbourhood of the city, being simply a freestone quarry that has lately been opened, or rather reopened, at Possil. The rock here is a fine-grained, compact sandstone, which occurs lower in the carboniferous series than the well-known sandstone of Bishopbriggs. It is valuable not only for its wearing properties, but also—the strata being nearly horizontal and very continuous—for the great size and regularity of the blocks that may be detached from it. Some of these, which are now being taken out and prepared for a public work, measure from 50 to 60 square feet, and must be not less than four or five tons in weight. At one part a good seam of coal is being wrought for the use of the engines on the ground. In another place a “felstone dyke” has cut through the strata, causing a displacement to some extent, and furnishing a good example of what are called “Slickensides,” as well as of the hardening effects of heat along the line of fissure. But these were not the points which we had specially come to examine. It is well known that This 250-word extract was created in the absence of an abstract