354 



These Sucia and Komooks beds are also almost certainly representa- 

 tives of those of the ~New Jersey Greensand series, containing Ammo- 

 nites complexus, Flacenticeras placenta. Nautilus DeJcayi, Baculites ovatiis, 

 GrypJicea vesicularis, Inoceramns Barahini, &c., as well as of the Upper 

 Chalk of Europe. 



Smithsonian Institution, Washington City, June, 1871. 



CARBONIFEROUS SPECIES. 

 BRACHIOPODA. 



Genus PRODUCTUS, Sowerby. 



Productits latissimus, Sowerby. 



Plf.te 1, fig. 1, 



Productm laUssimvs, Sowerby (1822), Mineral Conch., pi. .330.— Phillips (1836), Geol. 

 Yorks., ii, pi. viii, fig. 1.— DeKoninck (1847), Monogr Chonetes et Prod., pi. 

 ii, fig. 2; and pi. iii, fig. 2.— Davidson (1861), Scottish Carb. Brach., pi. ii, 

 figs. 8, 9; and (1857), Monogr. British Carb. Brach., 145, pi. xxv, figs. 1-4. 



Shell attaining a large size, thin, rather depressed, much wider than 

 long, with a sabsemicircular outline; anterior margin not produced; 

 hinge-line long, straight, but apparently not quite equaling the greatest 

 breadth. Ventral valve moderately convex or arched, with a regularly- 

 increasing curve from the front to the beak; anterior margin not pro- 

 duced and presenting a more or less nearly semicircular outline ; beak 

 incurved, but not prominent ; lateral extremities slightly rounded ; 

 ears more or less arched, and not in any way defined from the convexity 

 of the central region, which is nearly or quite without a mesial sinus ; 

 scars of divaricator muscles distinct and subquadrate ; surface without 

 concentric wrinkles, and marked by moderately distinct, rounded, 

 rather small, radiating costse, or coarse striae, that generally increase by 

 intercalation, and number about four or five in the space of 0.20 inch, 

 near the front. Dorsal valve unknown. 



Length, 1.67 inches ; breadth, about 2.53 inches ; convexity, 0.71 inch. 



Although I have seen only very imperfectly-preserved specimens of 

 this shell, they agree so nearly in almost all of their known characters 

 with F. latissimus of Sowerb}^ that I can scarcely doubt their identity 

 with that species, which has not, I believe, before been even pro- 

 visionally identified from any American locality. None of our speci- 

 mens show the little short spines seen on the ventral valve of Sowerby 's 

 species, but they are all more or less worn, while some slight remains 

 of what appear to be the bases of a few of these spines are seen on some 

 of the specimens. 



At first I was rather inclined to think this shell might belong to the 

 closely-allied P. giganteus of Martin ; bat the fact that well-preserved 

 internal casts of the ventral valve show no traces of the cavities for the 

 reception of the internal spiral arms, such as occur in P. giganteus, 

 favors the conclusion that it more probably belongs to P. latissimus. 

 It also agrees with the latter, and differs from the former, in having its 

 ears passing gradually into the convex part of the shell without any 

 depressions to mark the limits between these parts. This latter char- 

 acter, and the laterar extension of the ears, however, are better seen in 



