The evidence of the changing location of the poles is recorded -if the rock materials deposited by the polar ice-cap, such as moraines and thinly-bedded clays, by the polishing and scratching of the surface of the bed rock, and in other ways. In the early days of the single land-mass the Antarctic was on the Equator, as also was Alaska, North Greenland, Scandinavia and Siberia. The present sites of Peiping and Hongkong moved back and forth across the Equator; in the beginning the South Pole stood in Egypt Then the crustal movement brought the Sahara desert under the Pole, while in front of the moving mass of Sial the Siberian or Chinese geosyncline was. formed. After that the movement in the opposite direction gradually brought the Mediterranean region again under the polar ice, and the pressure exerted by the moving mass against the present west coast of America created the Rocky Mountain and Andean gebsynclines.
A study of the relationships of the strata in all parts of the earth has brought to light clear evidence that the sea transgressed simultaneously into all the geosynclines, and that at the end of the transgression a retreat set- in everywhere. That can only signify a rise of the sea level followed later by a corresponding fall. Rise and fall constitute together a Pulsation period, a pulse-beat of the earth due to the swelling of the sea-bottom on heating—thus raising the ocean surface—and to a sinking due to contraction on cooling and dissipation of the heat,
Text read from the printed page and cleaned; old type leaves the occasional error.