Page:Transactions of the Geological Society, 1st series, vol. 1.djvu/317

 range, for the road at this place makes a turn towards the hill, and on the left hand side of it, after proceeding a short way to the south, there appear several thin strata also bearing N. and S. and nearly vertical; the slight inclination they have from that position is towards the west. They consist of an alteration of a very compact argillo-quartzose sandstone, and containing a few impressions of terebratulites; of another rock similar to this, but much mixed with calcareous particles; and of a limestone, which contains a great number of the shells I have just named.

§ 48. Proceeding farther south, the road inclines towards the west, and is cut through a compact quartzose sandstone, similar to that mentioned in the preceding section, and containing impressions of madreporites and of terebratulites. It is here however mixed with a considerable quantity of mica, has a slaty structure, and breaks into rhomboidal fragments; giving it very much the appearance of a grauwacke slate. It occurs in thin strata, the bearing of which continues parallel to the direction of the range; but they dip east at an angle of about 60°. The road very soon turns to the westward, at a right angle to its former direction, and as it is still cut through the rocks, exhibits a transverse section of them; and in the space of about a quarter of a mile, they display some very remarkable changes in their mode of stratification. The inclination of the compact sandstone diminishes for some way as it recedes from the hill, but it again begins gradually to increase: to this rock succeed thin strata of an argillaceous limestone coated with a slaty clay, the inclination of which becomes more and more considerable. Thin strata of an argillaceous rock now appear, which very soon acquire a vertical position; they continue so for a short way, and then begin to dip towards the west, with a gradually diminishing angle of inclination. By the fall of the hill, the road very soon comes upon