Gazetteer of the State of Maryland

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Excerpt from Gazetteer of the State of Maryland: Compiled From the Returns of the Seventh Census of the United States, and Other Official Documents, To Which Is Added, a General Account of the District of ColumbiaThe later tertiary or post pliocene, which represents the epoc next antecedent to the introduction of the human race, occurs in Maryland only in limited patches. The principal one is in St. Mary's cbuntyu To this period are referred the nume rous beds of oysters which skirt the low margins of the islets and rivers of Mary land, and which are usually attributed to the agency of the aborigines. The deposit in St. Mar 's county is interesting, as containing several southern species, and par ticularly the gnathadoa comm, which is now found only in the warmer waters of the Gulf of Mexico, a fact indicating the prevalence in this region of a climate like that of Florida, at the period of the formation of this deposit. The miocene formation, which underlies the last-named deposits, is the most widely extended of the tertiary beds. The principal marl beds are in this formation. It occurs near Chestertown, Wye Mills, on Choptank river, near Easton, and at other places near the Eastern Shore, also through the counties of St. Mary's, Calvert, ac, Within the miocene, at Piscataway, has been traced a remarkable bed of silicious clay, entirely composed of silicious cases (of infusoria) so minute as only to be detected by a powerful microscope, yet containing distinct specific characters, en abling us to refer them to the miocene. Of the shells in the miocene deposits in this state, about seventeen per cent. Have been identified with living species. Thus, at this remote period, the peculiar distribution of living mollusca, which now exists, had begun to prevail in the region of Maryland, while at this geological era the fauna were so distinct from the present, that four-fifths of the species now living had not come into existence.About the PublisherForgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.comThis 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.