OAEBONIFEEOUS PERIOD. 115 



Lepta'tia suteafa Fischer, 1837, Oryct. du Gouv. de Moscou, pi. xxiii, fig. 2 (not Sowerby). 

 Productus semipunctatus Shepbard, 1838, Amer. Jour Sci., xxxiv, fig. 9. 

 Productus punctatus de Koniuck, 1843, Animaux Foss. Carb. Belg., 196. 

 Productus punctatus de Verneuil, 1845, Russia and the Ural Mountains, ii, 27G. 

 Productus vittatus Hall, 1858, Geology of Iowa, i, pt. ii, 639. 

 Productus punctatus Davidson, 1860, Monog. British Carb. Brachiopoda, 172. 

 Productus tuhulospinus McChesney, 1860, Descr. New Paleozoic Fossils, 37. 

 Productus imnctatus Meek, 1872, U. S. Geol. Surv. Nebraska. 



Shell large, tMn ; outline varying from imperfectly four-sided, the nar- 

 rowest side being the posterior one, to subovate ; sometimes wider than 

 long, but oftener longer than wide ; cardinal margin almost invariably 

 shorter than the width of the shell at any part in front of it ; anterior border 

 broadly rounded, but usually a little emarginate at the middle ; sides 

 flattened, by which means the lateral margins are somewhat straightened ; 

 ears small. 



Venti'al valve broadly arcuate from front to rear, in which direction 

 there is also a broad mesial flattening of the valve, with usually a shallow 

 but distinct mesial sinus along its middle ; umbo prominent, nan-ow, beak 

 small, incurved, and projecting slightly over the cardinal margin. Dorsal 

 valve moderately concave ; beak concave ; mesial fold slightly raised, 

 extending along the visceral and anterior portions of the valve. 



Surface of both valves marked by rather numerous and regular con- 

 centric folds, which are smaller at the beak and borders than elsewhere 

 upon adult shells, and smaller and more indistinct upon the dorsal than 

 npon the ventral valve ; interspaces between the concentric folds plain ; 

 folds supporting numerous spines of various sizes, but all small, and all more 

 or less appressed. 



Length of the specimen figured, four and a half centimeters ; breadth, 

 at the broadest part, four centimeters ; but this is rather smaller than the 

 average size of adult shells. 



This species is known throughout the whole Coal-Measure series of 

 the United States, especially in the valleys of the Mississippi and Missouri, 

 and is also a common Carboniferous species in Europe. Besides its range 

 through all the strata of the Carboniferous period in this country, examples 

 are frequently found in the Subcarboniferous strata of Missouri, Illinois, 



