olumn of matter and the expansive
force beneath them. These beds I conceive, when consolidated, to
constitute the gneiss formation.
"The farther the process of expansion proceeded in depth, the more was
the column of liquid matter lengthened, which, gravitating towards
the centre of the globe, tended to check any further expansion. It is,
therefore, obvious that after the globe settled into its actual orbit,
and thenceforward lost little of its enveloping matter, the whole
of which began from that moment to gravitate towards its centre, the
progress of expansion inwardly would continually increase in rapidity;
and a moment must have at length arrived hen the forces of expansion and
repression had reached an equilibrium and the process was stopped from
progressing farther inwardly by the great pressure of the gravitating
column of liquid.
"This column may be considered as consisting of different strata, though
the passage from one extremity of complete solidity to the other of
complete expansion, in reality, must have been perfectly gradual. The
lowest stratum, immediately above the extreme limit of expansion, will
have been granite barely DISAGGREGATED, and rendered imperfectly liquid
by the partial vaporization of its contained water.
"The second stratum was granite DISINTEGRATED; aqueous vapor, having
been produced in such abundance as to be enabled to rise upward,
partially disintegrating the crystals of felspar and mica, and
superficially dissolving those of quartz. This mass would reconsolidate
into granite, though of a smaller grain than the preceding rock.
"The third stratum was so disintegrated that a greater part of the mica
had been carried up by the escaping vapor IN SUSPENSION, and that of
quartz in solution; the felspar crystals, with the remaining quartz and
mica, SUBSIDING by their specific gravity and arranging themselves in
horizontal planes.
"The consolidation of this stratum produced the gneiss formation.
"The fourth zone will have been composed of the ocean of turbid and
heated water, holding mica, etc., in suspension, and quartz, carbonate
of lime, etc., in solution, and continually traversed by reciprocating
bodies of heated water rising from below, and of cold fluid sinking from
the surface, by reason of their specific gravities.
"The disturbance thus occasioned will have long retarded the deposition
of the suspended particles. But this must by degrees have taken place,
the quartz g
|