III.—Æolian Sandstone

Extract

As bearing upon the subject of Mr. J. Arthur Phillips's interesting and valuable paper in the last number of the Quarterly Journal of the Geological Society, entitled, “On the Constitution and History of Grits and Sandstones,” a description of a cliff section of blown sand now to be seen on the coast at Crosby may not be without value. The section in question, which attracted the attention of a local geologist, Mr. William Semmons, and myself, is at a point on the coast where the sea is encroaching upon the sand-dunes, and washing them away at the base leaves the face almost vertical. The resemblance of the sand to rock is most striking, presenting all those peculiarities of cross-bedding and lines of erosion we are familiar with in some of the Triassic sandstones of the neighbourhood. During the last twelve years, in walks along the shore, I have often observed the laminations of the blown sand disclosed by denudation, but never so strikingly as in the present case. The beds not only display delicate laminations, but stand out in ribs and cornices, simulating Gothic mouldings in pi'ofile. On trying how so loose a material as blown sand could retain these projecting forms, I was surprised to find the projections comparatively hard and solid. On breaking a piece off, the reason became apparent; for instead of the usually dry incoherent grains of sand, below the surface-skin the sand was quite damp. A very little addition of siliceous or calcareous cement would turn the mass into rock.