The Old Red Sandstone is one of two red bed sequences of sedimentary rock in the UK. The Old Red Sandstone describes a suite of sedimentary rocks deposited in a variety of environments during the Devonian but extending back into the late Silurian and on into the earliest part of the Carboniferous. It is dominated by alluvial sediments with conglomerates at its base, and progresses to a combination of aeolian, lakes and river sediments. The familiar red colour of the rocks from the presence of Iron Oxide. This particular example is from the Lower Devonian of Gloucestershire. Supplied by weight in lots of 1 kilogram, the size of pieces will vary.
