The calcareous sands which lie between the limestone-beds of the Inferior Oolite, above, and the clays of the Upper Lias, below, have from the time of Dr. William Smith until now been referred to the Oolitic group, and described in books as “the sands of the Inferior Oolite.” These sands exhibit a very uniform lithological character throughout their entire range in England, although they differ much in thickness in different localities, thinning out or even altogether absent in some places, but attaining a considerable development in others; in this respect they do not differ from the great oolitic limestone-beds themselves, forming so important a feature in the geology of Gloucestershire; as those bold mural escarpments of freestone which impart such a picturesque effect to Leckhampton, Birdlip, and Painswick Hills thin out and almost disappear in a run of less than twenty miles from these typical sections. If we trace the so-called “Sands of the Inferior Oolite” from Cheltenham southwards, we find them gradually thickening as we proceed by Crickley, Cooper's, and Painswick Hills, to Beacon, Frocester, and Wotton-under-Edge, where fine sections are exposed. The oolitic limestones, including the pea-grit, upper and lower freestones, and the intervening oolite marl, which are about 190 feet thick at Leckhampton, gradually diminish in thickness near Stroud, and in the neighbourhood of Bath are represented by about 60 feet of freestone, the pea-grit and oolite-marl having entirely thinned out.