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

NORTH AMERICA AT THE POLE 2O1
gin of error. This new expansion, called the "Tazewell Advance/'
apparently carried the Wisconsin icecap to its maximum
extension and greatest volume.
d. The Tazewell Advance was interrupted by a prolonged
period of warmth and recession called the "Brady Interval"
or "Brady Interstadial." This lasted between three and four
thousand years. It began before 16,720 years ago, and ended
sometime after 14,042 years ago. The ice retreated a long
way.
e. A fourth advance of the ice sheet beginning about
13,600 years ago, and continuing to about 12,120 years ago
(called the "Gary Advance"), was followed by the "Two
Creeks Interstadial," an interval of warmth and recession,
about 11,404 years ago.
f. A fifth advance of the ice, referred to as the "Mankato
Advance," appears to have taken place between 10,856 and
8,200 years ago. The high point of this advance is called the
"Mankato Maximum." Another writer, Emiliani, finds that
a sixth expansion of the ice sheet, the "Cochrane Advance,"
took place less than 7,000 years ago (132).
g. There was a sudden, virtually complete disappearance
of the ice sheet (which had, however, according to Flint, been
getting thinner ever since the Tazewell Advance) (375:177).
It disappeared in an extraordinarily short period, as shown
by a postglacial date from Cochrane, Ontario, 6,380 years ago.
h. The significance of the postglacial date from Ontario
(close to the center of the former ice sheet) is increased when
we it compare with the date of the postglacial Climatic Op
timum, which Flint finds to have occurred between 6,000 and
4,000 years ago. The climate during the Optimum, according
to Brooks (52:296-97), averaged about 5 degrees warmer
than at present. There is a very difficult problem here of ac-
counting for the velocity of these events. It is obvious that
the cold glacial climate of North America must have warmed
up to something like the present prevailing temperatures
before it could warm up still further to the point reached
in the Optimum. But if so, could the whole wanning process