The Earth's Shifting Crust by Charles Hapgood - wire of information

CONTINENTS AND OCEAN BASINS 15!
composition of continents and of the crust under the
oceans, a difference that has been verified for the uppermost
few miles of the continental and oceanic sectors of the crust,
but not for the greater depths.
Now, if everything below, say, a depth
of ten miles were
layered everywhere at equal depths with rock of equal
densities, no quarrel whatever could be had with the geophysicists
who argue for the permanence of continents and
ocean basins. For in that case, only a massive change in the
distribution of the superficial layers of light and heavy rock
could change the distribution of continents and ocean basins.
Granitic or sedimentary rocks at the surface .would have to
be destroyed or created in enormous quantity to destroy or
create a continent.
It is entirely otherwise with the structure as suggested by
Daly and as revealed in the recent geophysical surveys. To
understand this it is necessary only to visualize that the rela-
tive elevation of the surface at any point is determined by
the average density of the entire column of matter between
the surface at that point and the bottom of the crust, where,
presumably, the inequalities at different points are pretty
well averaged out.
If the crust is not definitely layered, if, as both Daly and
recent geophysicists agree, there are radical variations in the
structure, then the vital changes may occur at any depth,
deep down as well as at the surface. There is reason to believe
that massive changes may occur more easily deep down
than at the surface. Thus, the crust might be weighted in its
lower parts by an intrusion of a great mass of molten rock
of high density from below, a very likely result of a displacement.
In either case, whether the addition of the heavy matter
occurred near the surface or far below it, the result would
equally have been a depression of the surface, with a con-
sequent encroachment of the sea. Obviously, a repetition of
such movements could subside a continent to a great depth,
without altering the composition of the superficial forma-
tions.