TRANSACTIONS OF WAGNER 

 IOQ2 



TERTIARY FAUNA OF FLORIDA 



coast, where it takes the place in faiinal economy occupied by the typical group 

 in the more northern waters. 



The Eocene species, which might be, perhaps, included in this group and 

 are excluded by their characters from any of the other groups of the genus, 

 are few in number. C. Harrisi Vaughan, 1896, from the Lower Claibornian 

 of Louisiana, which, except that the shell does not gape, might be supposed 

 to belong to Tropidocardium and is believed to have large, flat spines exter- 

 nally, and C. Cooperi Gabb,* of California. There is a poorly preserved species 

 with numerous rounded ribs found in the lower marls at Shiloh, New Jersey, 

 which was referred by Whitfield in his description of the marl fauna to C. 

 craticidoide Conrad. A comparison with the true craticuloide , which is a 

 Plum Point Miocene shell with thirty very elevated narrow ribs, shows that 

 this identification is incorrect. The Shiloh species, in the absence of better 

 material, does not seem to differ from casts in the limestone of Jacksonboro', 

 Georgia, referred by Conrad to his ill-defined Shell Bluff group, and both 

 appear extremely close to, and possibly identical with, C. eversiun Conrad, 

 described from the Vicksburgian Oligocene in 1848. Another species, C. 

 vicksburgense, was described by Conrad from the same horizon at the same 

 time. 



In the Miocene there is a fine showing of these shells. C. acutilaqueatum 

 Conrad (Medial Tert., p. 34, pi. xviii., fig. 2, 1839) has been obtained from 

 the Miocene of Alum Bluff, Florida; from that of the Natural Well and 

 Magnolia, Duplin County, North Carolina ; Suffolk, on the Nansemond River, 

 Grove Wharf, on the James River, and Petersburg, Virginia. It is somewhat 

 compressed, elevated, and has about forty ribs. C. laqueatum Conrad, 1831 

 {op. cit., p. 31, pi. xvii., fig. i), is a somewhat similar but more inflated and 

 trigonal species with thirty-four to forty-one ribs, and is usually found in a 

 very decayed state. It is known from the Natural Well and Magnolia, North 

 Carolina; from the north end of the Dismal Swamp, from Cove Point and 

 Petersburg, Virginia, Jones Wharf and St. Mary's, Maryland. It is the 

 C. ingens Wagner, 1839. C. leptopleura Conrad, 1841, from Calvert Cliffs, 

 Maryland, is a rare species, notable for its relative width and thirty-one dis- 

 tant, angular, carinated ribs. I have not succeeded in collecting this species 

 in its typical form, and specimens which have been referred to it from Plum 

 Point seem to differ more or less from Conrad's figure. A Cardimn modestum 

 Conrad (1855, Pacific R. R. Reports, vol. v., p. 322, plate iii., fig. 15) is de- 



'■ This is, however, claimed to be really a Cretaceous species. 



