FREE INSTITUTE OF SCIENCE 



1525 



TERTIARY FAUNA OF FLORIDA 



Thracia decUvis Conrad, Am. Marine Conch., p. 44, pi. ix., fig. 2, 1831 ; not of Pennant, 



1778. 

 Thracia declivis Reeve, Conch. Icon., Thracia, sp. 4, 1859; not of Pennant. 



Miocene of Maryland, on left bank of Patuxent River a quarter of a mile 

 south of Burch, Harris ; of the upper bed at Alum Bluff, Calhoun County, 

 Florida, Burns ; living from Labrador to Cape Hatteras in three to fifteen 

 fathoms, sand or mud. 



The fossils are in poor condition but resemble T. Conradi except in the 

 higher anterior dorsal arch, and in being thicker and heavier than any recent 

 specimens I have seen. One cannot without better material be certain of the 

 identity of the recent and fossil specimens, for which reason I prefer to regard 

 the latter as forming a variety Harrisi pending the receipt of further informa- 

 tion. 



Thracia transversa H. C. Lea. 



Thracia transversa H. C. Lea, Trans. Am. Phil. Soc, N. S., ix., p. 237, pi. xxxiv., fig. 11, 

 184s; Conrad, Proc. Acad. Nat. Sci. Phila., xiv., p. 572, 1863; Meek, Checkl. Mice. 

 Fos. N. Am., p. II, 1864. 



Miocene of Petersburg, Virginia, Lea and Burns ; and of the York River, 

 near Yorktown, Virginia, Harris. 



Only a few specimens of this small species have been found and the ma- 

 terial is insufficient for a critical comparison, but they appear suspiciously like 

 the young of T. tnincata Mighels and Adams, 1842: not T. truncate Turton 

 (as Anatina), 1822; = 7. septentrionalis Jeffreys, Ann. Mag. N. Hist., Oct., 

 1872, p. 238. 



Lea's figures were very poor, but the present is the only species found at 

 Petersburg and the identification is subject to little doubt. 



Other East American species of this group are T. myopsis Moller, 1842 

 (-)- T. Couthonyi Stimpson, 1851) ; T. nigosa Orbigny (as of Conrad MS.), 

 1846, which is extremely close to T. distorta Montagu, 1808, and T. siniilis 

 Couthouy (-)- T. Rushii Pilsbry), 1842. None of these has been authentically 

 reported in the fossil state as far as I have been able to learn. On the Pacific 

 side are T. trapezoides Conrad, 1849, from the 01igocene(?) of Astoria, Ore- 

 gon; T. mactropsis Conrad, 1856, from the Miocene of California, not since 

 recognized; and T. ventricosa Conrad, a nude checklist name of 1864, referred 

 to the Miocene of Oregon. Thracia myccformis Conrad, from the Miocene marl 

 of Shiloh, Cumberland County, New Jersey, is positively identified with Saxi- 

 cava bv Professor Whitfield in his studv of the Miocene Mollusca of New 



