PUDDING-STONE—FLINT—CHERT, &c.
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times sending off branches. An example of it was feen lately in a
quarry on the sea-ſhore near Musselburgh, which resembled the
trunk of a vast tree sending out branches in all directions.
Sand-stone is of very various hardness. In some the fand has but
a weak degree of cohesion. In others the grains are so closely and
strongly coherent, that the stone has the appearance of solid flint,
and cannot be wrought as a free-stone.
4to, The ſtrata of what I called gravel-stone have been formed
in the fame manner as sand-stone, only that gravel is intermixed
with the sand in the composition of the stone. From its appearance
this stone is named by the Englifh pudding-one ; and the name
has been adopted by foreigners.
Such are the strata, principally or totally composed of the hard
ſtony bodies. There are also some kinds of rock in which more or
less of them is contained, as granite, to be soon described; and the
more compounded kind of rock which abounds in this country, nam
WHIN-STONE, ſome kinds of which are a more coarse and compound
granite. The whin-ſtone often contains nodules and pebbles of all
different sizes, some of which are hard stones.
The ſchistuses also, or indurated argillaceous strata, often contain
a large proportion of quartz irregularly intermixed through them.
The hard stones constitute therefore a great part of the materials
of many strata and rocks. They are also found often in veins, or
otherwise interspersed through rocky or stratified matter. The spe
cies most frequently found in this state is quartz; but we also find
occasionally, crystal, chalcedony, agate, jasper, and flint.
Thère are great quantities of flint in England, interspersed in a
very irregular manner through the calcareous strata of chalk and
limestone, traversing and running through them in different direc
tions. As found in chalk, it is more especially named flint ; as oc
curring in limestones, it is named chert by the English.
From the appearance of this matter, as found in this state, there
