The geological history of New York state - Softcover

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1914 Excerpt: ...at the western margin of the present Coastal plain and has been traced from Martha's Vineyard, through Nantucket, Long Island, Staten island, Northern New Jersey, and southward into Georgia. Passing seaward the strata dip under those of later age (see figure 22). On Long Island, Potomac outcrops occur only along the northwestern border but these beds no doubt dip under the more recent deposits of the rest of the island. The maximum thickness of the Potomac series is only about 700 feet. Along the Atlantic coast certain deposits which should come between the Lower and Upper Cretacic are missing, and the Upper Cretacic beds rest upon the eroded surface of the otherwise undisturbed Lower Cretacic. Thus we know that there was a gentle upward oscillation of the land toward the end of the Lower, or beginning of the Upper, Cretacic, after which a moderate amount of erosion of the Lower Cretacic beds took place. Then came another gentle submergence of the coastal lands when the Upper Cretacic strata were formed. The character and present extent of these deposits, and the fact that they are of marine origin, prove that this subsidence allowed a shallow sea to spread over practically all of what is now called the Atlantic Coastal phiin including most of Long and Staten islands in New York. Accordingly we learn that, for the first time since the close of the Paleozoic, did truly marine conditions prcx-ail over any portion of New York State, and also that Appalachia, the great land mass of the cast, which had persisted through the many million years of the Paleozoic and most of the Mesozoic, now disappeared under the Cretacic sea. The present surface distribution of the Upper Cretacic beds is much like that of the Lower Cretacic, and they also dip under the still later...