Page:Transactions of the Geological Society, 1st series, vol. 1.djvu/217

 first step of the ascent of Steeraway-hill) presents fragments of a bed of limestone, between which protrude masses of coarse globular greenstone; then occurs a bed of sandstone slate, or flagstone, at an angle of 35°, which is succeeded by a bed of limestone elevated at nearly the same horizontal angle; then come four more beds at an angle of 40°, being an alternation of sandstone and limestone, and the last of these reaches to about two thirds of the ascent of the hill; the remainder, together with the summit, consists of amorphous and sienitic greenstone, covered with fragments of sandstone slate strata, the inclination of which, as far as can be ascertained, approaches much more to horizontal than that of the preceding. Although for the sake of brevity and clearness I have characterized the above formation as an alternating series of four beds of sandstone and limestone, yet it must be observed that each limestone bed consists of several strata, each about a foot in thickness, composed alternately of compact limestone and of bluish-grey clayey marl filled with very delicate and brittle tubulites, the direction of the tubes being perpendicular to the plane of the strata.

An important geological question now occurs with regard to these beds, which in their composition and in the general line of their direction bear a close resemblance to the limestone of Wenlock Edge, though they differ so greatly in the amount of their horizontal angle; are they or are they not in the position in which they were first deposited? The negative side of this question appears to be supported by the impossibility of a bed of sandstone, and much more of clay marl (or mud as it no doubt was in its original state) being deposited on a plane at an elevation of from 30° to 40°, in such a manner as to constitute an extensive stratum of an uniform thickness, and that hardly exceeding a foot, for a depth of at least one hundred feet. The position also of the tubulites which pierce