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

8o EARTH'S SHIFTING CRUST
the cooling of the earth is less than it had been originally be-
lieved. . . ." (194:192). Bullard, reviewing
the third edition
of Harold Jeffreys's basic work, The Earth, notes the absence
of progress toward solving the problem of mountain build-
ing, since the second edition twenty-five years ago (59).
Pirsson and Schuchert, the authors of a general text on geol-
ogy, conclude a section on the cause of mountain building
with the statement: "It must be admitted, therefore, that the
cause of compressive deformation in the earth's crust is one
of the great mysteries of science, and can be discussed only in
a speculative way" (345:404).
What is the nature of this problem that has so far baffled
science?
/. The Problem of Crustal Folding
It is important to take into account the fact that there are sev-
eral different kinds of mountains, and that their origins may
be ascribed to somewhat different circumstances, even though
(as we shall see) they may be related to one underlying cause.
Some mountains are caused by volcanic eruptions. These consist
of piles of volcanic matter. Some of the greatest mountains
on the earth's surface are volcanic mountains. Many
of them are found on ocean bottoms, and when they rise to
the surface they form the island chains (such as the Hawaiians)
that are especially numerous in the Pacific. Sometimes
volcanic islands or mountains can be formed quickly, as was
the case recently in Mexico, where a large mountain,
Paricutfn, was developed in a few years to a height of several
thousand feet from a lava flow that started in a cornfield on
the level ground. Some mountains result from a vast flow of
molten rock that gathers under the crust at one spot and
domes it up. The causes of these events are unknown.
Many mountains, and even whole ranges of mountains, are
brought into existence in part by the cracking of the earth's
crust, accompanied by the tilting of the separated blocks. The