Excerpt from Guidebook: For the Transcontinental Excursion of 1912 Interruption of the Older Appalachians. The middle stretch of the older Appalachians, especially between New York and Philadelphia, is narrow, low, and interrupted. It is narrow, because of an inward bend of the over'apping coastal plain border, so that the breadth of the crystalline belt is reduced to 50 miles or less. Even this small breadth was once still smaller, for the overlapping coastal plain strata have been worn off from their original inland extension, stripping a formerly covered part of the crystalline peneplain; the stripped belt is frequently traversed by superimposed streams in narrow gorges, excellent examples of which occur near Philadelphia. The middle stretch is low, seldom exceeding 600 or 800 feet even along its inner border, because its uplift was moderate. Hence the older Appa lachian belt does not here constitute a formidable barrier between the coast and the interior, as is the case in New England and North Carolina. Finally, the upland of the middle stretch is interrupted, for it frequently includes infolded or down-faulted areas of weaker rocks, Which are now worn down to lowlands beneath the uplifted peneplain of the inclosing crystallines. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.