Bulletin, Issue 4

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Page 25 - Report of the progress of the Geological Survey of the State of Virginia for the year 1840.
Page 45 - A revision of the fossil ferns from the Potomac group which have been referred to the genera Cladophlebis and Thyrsopteris.
Page 19 - The oylter-fliells are ib united by a very ftrong cement, that they fall only when undermined, and then in large bodies, from one to twenty tons weight. They have the appearance of large rocks on the mores, and are wafted by the frequent wafhing of the fea.
Page 19 - That the whole of this extensive country, from the falls to the coast, is factitious, and of Neptunian origin, appears far from being hypothetical ; and the fossil teeth and bones, which accompany this memoir, and which with many hundred more, were dug out of a well at Richmond from the depth of 71 feet, prove that the deposition of the super-strata is not of a date sufficiently removed to have destroyed the soft and almost cartilaginous part of the joints, or to have injured the enamel of the tfelli.
Page 215 - ... movement, which is still in progress. It is this which has produced the estuaries and tide-water marshes that form conspicuous features of the existing topography. At the present time the waves of the Atlantic Ocean and Chesapeake Bay are at work tearing away the land along their margins and depositing it on a subaqueous platform or terrace. This terrace is everywhere present in a more or less perfect state of development, and may be observed not only along the exposed shores, but also on passing...
Page 219 - Sunderland, and Wicomico plains, which have been subjected to denudation for a much longer period of time. RECENT STAGE. • The land probably did not long remain stationary with respect to sea level before another downward movement was inaugurated. This last subsidence is probably still in progress. Before it began the...
Page 30 - CONRAD, TA Descriptions of new Genera and Species of Miocene Shells, with notes on other Fossil and recent Species. Amer. Jour. Conch., vol. iii, 1868, pp.
Page 38 - On the Geological Position of the Eocene Deposits of Maryland and Virginia: Amer.
Page 265 - Description. Fine gravel. Coarse sand. Medium sand. Fine sand. Very fine sand. Silt. Clay.
Page 212 - N"ear the beginning of Miocene submergence, certain portions of the sea bottom received little or no materials from the land, and the water in those places was well suited as a habitat for diatoms. These must have lived in the waters in countless millions, and as they died their silicious shells fell to the bottom and produced the beds of diatomaceous or infusorial...

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