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

126 EARTH'S SHIFTING CRUST
a periodic rise and fall of the sea-level, a slow pulsatory movement,
due apparently to alternate swelling and contraction of the seabottom
(183).
jo. Some Light from Mars
Some very significant facts emerge from recent studies of
other members of the solar system, especially from the work
of Dr. Harold Urey, The Planets: Their Origin and Development
(438). This is the work in which the theory of accretion
of planets is developed, in contradiction to the older theory
of the cooling globe. Dr. Urey also discusses the present state of
knowledge regarding the structure of the moon and Mars.
It appears that there are mountains on the moon, but in
Dr. Urey's opinion these have been created by collisions with
minor celestial bodies. Where the colliding body hit the
moon more or less head on, craters (the largest more than 100
miles across) were formed. Planetesimals that merely grazed
the moon's surface left long ridges and valleys. Where the
heat created by the impacts caused extensive rock melting,
vast lava floods apparently took place, which cooled off, in
tens or hundreds of thousands of years. The absence of air
and water has resulted in an absence of erosion on the moon's
surface, so that the features created by the collisions have
not been obliterated except in cases where the lava flows have
swamped them.
In the case of Mars, the story is different. Urey assumes
that Mars was once like the moon, both in size and in surface
features. The removal of these features, which no longer
exist, he thinks must have been due to the work of atmosphere
and water. He gives reasons for believing that Mars
did have more water at one time, but that it escaped from
the planet by a process that is also going on, more slowly, on
earth. He states:
. . . The surface appears to be smooth, a condition most easily
explained as due to the action of water during its early history and
no mountain building since then (438:65).