* William H. Hess, "The Influence of Glaciation in Ohio," in
"Bulletin of the Geographical Society of Philadelphia," vol. XV
(1917), pp. 19-42.


We have taken Wisconsin and Ohio as examples, but the effect of
glaciation in those States does not differ materially from its
effect all over southern Canada and the northern United States
from New England to Kansas and Minnesota. Each year the people of
these regions are richer by perhaps a billion dollars because the
ice scraped its way down from Laurentia and spread out over the
borders of the great plains on the west and of the Appalachian
region on the east.

We have considered the Laurentian highland and the glaciation
which centered there. Let us now turn to another highland only
the northern part of which was glaciated. The Appalachian
highland, the second great division of North America, consists of
three parallel bands which extend southwestward from Newfoundland
and the St. Lawrence River to Georgia and Alabama. The eastern
and most important band consists of hills and mountains of
ancient crystalline rocks, somewhat resembling those of the
Laurentian highland but by no means so old. West of this comes a
broad valley eroded for the most part in the softer portions of a
highly folded series of sedimentary rocks which are of great age
but younger than the crystalline rocks to the east. The third
band is the Alleghany plateau, composed of almost horizontal
rocks which lie so high and have been so deeply dissected that
they are often called mountains.