V.—Concretions

Extract

There is a fine exposure of the “Lower Greensand” in a railway cutting by Sandy Station on the G.N. and L. & N.W. Railways, presenting a nearly vertical section 50 or 60 feet in height. It consists almost entirely of clean sand, in parts falsebedded, and more or less coloured throughout by the presence of oxide of iron. The colour thus imparted to the sand varies from almost pure white, at the lower part, through shades of grey and yellow, to a deep rusty brown. There are here and there layers of hard ferruginous concretions in tabular, spherical, and many other forms, presenting a feature hitherto (so far as the writer is aware) unnoticed. This is a gradual passage from soft iron-stained sand to hard complete concretions, exhibiting the various stages in the process of their formation.