nd assumed in
its composition a highly crystalline character. Such is peculiarly the
case with the fundamental or gneiss deposits of the period. In the
overlying mica schist there is still much of contortion and disturbance;
whereas the clay slate, which lies over all, gives evidence, in its more
mechanical texture, and the regularity of its strata, that a gradual
refrigeration of the general mass had been taking place, and that the
close of the Azoic period was comparatively quiet and cool. Let us
suppose that during the earlier part of this period of excessive heat
the waters of the ocean had stood at the boiling point even at the
surface, and much higher in the profounder depths, and further, that
the half-molten crust of the earth, stretched out over a molten abyss,
was so thin that it could not support, save for a short time, after some
convulsion, even a small island above the sea level. What, in such
circumstances, would be the aspect of the scene, optically exhibited
from some point in space elevated a few hundred yards over the sea? It
would be simply a blank, in which the intensest glow of fire would fail
to be seen at a few yards' distance. An inconsiderable escape of steam
from the safety-valve of a railway engine forms so thick a screen, that,
as it lingers for a moment, in the passing, opposite the carriage
windows, the passengers fail to discern through it the landscape beyond.
A continuous stratum of steam, then, that attained to the height of even
our present atmosphere, would wrap up the earth in a darkness gross and
palpable as that of Egypt of old,--a darkness through which even a
single ray of light would fail to penetrate. And beneath this thick
canopy the unseen deep would literally "boil as a pot," wildly tempested
from below; while from time to time more deeply seated convulsion would
upheave sudden to the surface vast tracts of semi-molten rock, soon
again to disappear, and from which waves of bulk enormous would roll
outwards, to meet in wild conflict with the giant waves of other
convulsions, or return to hiss and sputter against the intensely heated
and fast foundering mass, whose violent upheaval had first elevated and
sent them abroad. Such would be the probable state of things during the
times of the earlier gneiss and mica schist deposits,--times buried deep
in that chaotic night or "evening" which must have continued to exist
for mayhap many ages after that beginning of things in which Go