Note: Different names are applied to the various kinds of
sandstone according to their composition; as, granitic,
argillaceous, micaceous, etc.
{Flexible sandstone} (Min.), the finer-grained variety of
itacolumite, which on account of the scales of mica in the
lamination is quite flexible.
{Red sandstone}, a name given to two extensive series of
British rocks in which red sandstones predominate, one
below, and the other above, the coal measures. These were
formerly known as the Old and the New Red Sandstone
respectively, and the former name is still retained for
the group preceding the Coal and referred to the Devonian
age, but the term New Red Sandstone is now little used,
some of the strata being regarded as Permian and the
remained as Triassic. See the Chart of {Geology}.