large inland seas, and in general allowing a free communication
with the ocean, we are very sure the effect would be widely different.

Under these circumstances, says Mr. Geikie, the "much wider extent of
sea being exposed to the blaze of the tropical sun, the temperature of
the ocean in equatorial regions would rise above what it is at present.
This warm water, sweeping in broad currents, would enter the polar
fiords and seas, and everywhere, beating the air, would cause warm,
moist winds to blow athwart the land to a much greater extent than they
do at present; and these winds thus distributing warmth and moisture,
might render even the high latitude of North Greenland habitable
by civilized man." So we see that it is necessary to look for such
geographical changes as will interfere with the movements of marine
currents.

Now, it is easy to see that comparatively small geographical changes
would not only greatly interfere with these currents, but might even
cause them to entirely change their course. An elevation of the northern
part of North America, no greater in amount than is supposed to have
taken place at the commencement of the Glacial Age, would bring the
wide area of the banks of Newfoundland far above the water, causing the
American coast to stretch out in an immense curve to a point more than
six hundred miles east of Halifax, and this would divert much of the
Gulf Stream straight across to the coast of Spain.<23>

Such an elevation certainly took place, and if continued westward,
Behring's Strait would also have been closed. It is to such northern
elevations, shutting out the warm ocean currents, that a great many
geologists look for a sufficient explanation of the glacial cold.

Prof. Dana says: "Increase in the extent and height of high latitude
lands may well stand as one cause of the Glacial Age." Then he
points out how the rising of the land of Northern Canada and adjacent
territory, which almost certainly took place, "all a sequel to the
majestic uplift of the Tertiary, would have made a glacial period for
North America, whatever the position of the ecliptic, or whatever the
eccentricity of the earth's orbit, though more readily, of course, if
other circumstances favored it."<24>

It may occur to some that if high northern lands be all that is
necessary for a period of cold, we ought to have had it in the Miocene
Age, when there was a continuous land connection between the lands of
high polar