in wheaten loaves and distributed every Sabbath morning after
service. The dole still survives, though the day has been altered to
Saturday, each week sixty-seven loaves being given away.

DOLERITE (from Gr. [Greek: doleros], deceptive), in petrology, the name
given by Hauy to those basaltic rocks which are comparatively coarse
grained and nearly, if not quite, holocrystalline. As may be inferred
from their highly crystalline state they are very often intrusive, and
occur as dikes and sills, but many of them form lava flows. Their
essential minerals are those of basalt, viz. olivine, augite and
plagioclase felspar, while hornblende, ilmenite, apatite and biotite are
their commonest accessory ingredients. The chemical and microscopic
features of these minerals agree generally with those presented in the
basalts, and only their exceptional peculiarities need be mentioned
here. Many dolerites are porphyritic and carry phenocrysts of olivine,
augite and plagioclase felspar (or of one or more of these). Others,
probably the majority, are non-porphyritic, and these are generally
coarser grained than the ground-mass of the former group, though
lacking their large conspicuous phenocrysts. The commonest type of
structure in dolerite is the ophitic, which results from the felspar of
the rock having crystallized before the augite; the latter mineral forms
shapeless masses in which the idiomorphic felspars lie. The augite
enclosing the felspars is well crystallized, though its continuity is
interrupted more or less completely by the numerous crystals of felspar
which it envelops, and in polarized light the former often behaves as a
single individual over a considerable area, while the latter mineral
consists of independent crystals. This structure may be so coarse as to
be easily detected by the unaided eye, or so fine that it cannot be seen
except in microscopic sections. Some of the porphyritic dolerites have
ophitic ground-masses; in others this structure is imperfect
(subophitic); while in many the augite, like the felspar, occurs as
small and distinct individuals, which react differently on polarized
light, and have the outlines of more or less perfectly shaped crystals.
Ophitic structure is commonest in olivine-dolerites, though the olivine
takes no part in it.

The quartz-dolerites are an important group, hardly less common than the
olivine-dolerites. They contain a small amount of quartz, and often
micropegmatite, a