* VI 



The beauty, variety, and peculiar character of our Tertiary 

 fossils, are such as to recommend them to the notice of the 

 mere Conchologist ; but when viewed in connexion with Geolo- 

 gical phenomena, they will prove, in consequence of their vast 

 extent and continuous beds, even more important than the most 

 celebrated contemporaneous deposits in Europe. This region 

 has scarcely as yet met the eye of a practical Geologist, since 

 the importance of extraneous fossils has been duly appreciated, 

 or surely we should have had a valuable detailed account of the 

 scientific treasures which extend almost without interruption 

 from New Jersey, inclusive, to the Gulf of Mexico. 



Three different classes of organic remains will be remarked 

 by every observer of the formations in question,; and examples 

 of each are included in the western peninsula of Maryland. 

 The first consists chiefly of extinct species ; the second is a mix- 

 ture of extinct species with others still inhabiting the coast of the 

 United States, and the third embraces existing species alone.. 

 It is but lately that deposits similar to the latter have attracted 

 the attention they merit, and they seem to prove that the Ter- 

 tiary formations pass insensibly into each other, and that a new 

 creation of marine shells had gradually taken the place of the 

 old; It is certain that the lower, or oldest of these strata, al- 

 ways form the western boundary of the newer beds, and thg 

 most recent strata rest 'only on the eastern limits of this mid- 

 dle class of depositions. In those localities where recent and 

 extinct species are indiscriminately mingled, a few shells occur, 

 which although they cannot be satisfactorily referred to existing 

 species, resemble them in such a manner as to excite a sus- 

 picion that they may be varieties occasioned by a difference of 

 temperature, &c. between the ancient ocean and the present. 



The banks of the larger rivers of the Tertiar} r region contain 

 incredible numbers of shells, which are profusely scattered on 

 the sands beneath. These banks are often high and perpendi- 

 cular, composed of sand and clay, so very friable, that immense 

 masses, loosened by the frost, frequently fall, strewing the mar- 

 gins of these rivers with, the Pines which skirt their elevated 

 bluffs: thus at a place called the Rocks, on James River, a 

 few miles from the village. 1 of Smithfield, it is difficult to walk 

 along the shore, when the tide is in, in consequence of fallen 

 trees, and masses of clay filled with innumerable shells. This 



[16] 



