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

CONTINENTS AND OCEAN BASINS 149
then, no doubt, shallow seas; after that, in some cases, very
deep sea, then again shallow sea, and finally again land, all in
the same place. But the interludes of deep sea may have been,
in many cases, very short, and the sedimentation resulting
may have never been consolidated. Thus the deep sea could
come and go, and nobody the wiser. New evidence bearing
on this is problem now available as the result of recent Soviet
oceanographic work in the Arctic. Soviet scientists have
found evidence that the Arctic Ocean itself has existed only
since the comparatively recent Mesozoic Era (364:18). We
shall return to this evidence.
It seems reasonable to conclude that at least some of the
problems presented by the continents and ocean basins are
soluble in terms of the principles described in this and previous
chapters. Land links may be explained as the conse-
quences of mountain formation on the sea bottom; temporary
and limited uplift or subsidence of large areas may result
directly from their poleward or equatorward displacement.
The major changes, howeverthe enormous elevations and
subsidences, the destruction and creation of continentsrequire
us to examine the deepest possible consequences and
implications of crust displacement. We must now undertake
this deeper examination. This requires us to take another
glance at the nature and structure of the crust of the earth,
to its full depth, as far as our present geophysical knowledge
permits.
6. The Deeper Structure of the Earth's Crust
It has, until lately, been the impression that the earth's crust,
considered as a crystalline layer between 20 and 40 miles
thick, was itself composed of various layers, with rocks of
increasing density at increasing depths.
This would have
been a natural development with a cooling earth, for it might
be supposed that the lighter materials in a liquid would tend
to float on the heavier ones, and would solidify in the order