194 LEA'S DESCRIPTION OF A FOSSIL SAURIAN 



polished rhombic fish scales in the bituminous shales near Farmville, and at Leakes- 

 ville, in North Carolina." 



In regard to the character of the Molluscs which may have inhabited this formation, 

 it is difficult to adduce them as much evidence, where so little is known. The 

 almost total absence of fossil shells, or impressions, is most remarkable in the New 

 Red Sandstone here, as it is, also, in Europe. In the Palseontological tables of M. 

 D'Orbigny, there are a few genera given, as existing in his Saliferien, (the upper por- 

 tion of the Trias,) and among the Lamellibrancliia is the genus Posidonia, a species of 

 which Prof. W. B. Rogers states he has found in Virginia, and which he refers to a 

 well-known species in the Keuper, or uppermost division of the Trias, known as P. 

 Keuperi* He also mentions that, in Cumberland County, Virginia, in the Yellow 

 Brown Sandstones, he found a spiral univalve and a rhombic fish scale. 



To this I may add a minute species of Gasteropoda, which I suspect belongs to the 

 genus Loxonema\ and which I have observed in a polished specimen of the Potomac 

 Marble, J and for which I propose the name of Loxo. Pomeliatia. These are the only 

 Molluscs which have been, to my knowledge, found in the New Red Sandstone 

 of this country. The question might now be asked, are these of marine or fresh 

 water origin ? I think it would be difiicult to answer, with any degree of 

 certainty. The shell of Posidonia has evidently been, in all the species, exceed- 

 ingly fragile, and, as far as my knowledge extends, the casts only have been 

 observed, and those rarely perfect. I doubt very much whether those found in 

 the Carboniferous Formation can be properly placed in that genus, particularly if 

 they be found in the slates of the coal seams, which are probably of fresh water 

 origin. § In the slates taken from the anthracite beds of Peimsylvania, I have 

 found bivalves, which I should consider so much allied to the form of Posidonia, 

 as not to think of separating them, had they not been in a coal slate. At 

 the same time, I must say that the same slate contained impressions of a 

 lamellihranc, which has all the external characters of the genus Modiola ; which, 

 however, would not exclude it from fresh water origin, as we have a living genus, 



* But a few years ago it was considered in vain, Mr. W. King, author of " Permian Fossils," says, to look for 

 fossils in this Formation in Europe. That there are now found fishes, shells, and impressions of footsteps, probably 

 a Batrachian. That in Germany the Posidonia minuia is stated to pervade the new red system, from the Keuper 

 to the Bunter sandstone, inclusive, but in England it is peculiar to the upper Formation, and very abundant in 

 some of the beds. p. 338. 



■j" The genus Loxomma was established by Phillips, for a shell near to Chemnitzia, and belongs to the Family 

 Melaniana. It has been found in the Silurian and Permian Formations. 



J This specimen, which my friend Samuel Powel, Esq., submitted to my examination, is the only one, of this 

 conglomerate limestone, in which I have been enabled to detect the smallest remains of a mollusc. There are in 

 it several fragments of whorls, and only one which has as much as three entire whorls. These present very 

 closely the form and size of L. Geiniiziana, King, from the Permian of England. The specimen is presented to 

 the Academy by Mr. William Struthers. 



§ The fossil plants, chiefly of the order Felices, which prevail in these slates to such an extent, must have been 

 nourished in marshy fens of fresh water. 



