DESCRIPTIONS OF SPECIES. 367 



? Archimedes limestone: Independence County, Ark. 

 ? Marshall shale: Independence and Stone counties, Ark. 

 ? Fay etteville shale: Independence County, Ark. 

 1900. Productus cora. Beede, Univ. Geol. Surv. Kansas, Kept., vol. 6, p. 75, pi. 11, figs. 1-lf. 



Upper Coal Measures: Kansas City, Eudora, Lawrence, Lecompton, Topeka, Geary County, 

 Melvern, Osage County. 



The shells which I have referred to this species vary much in size, but agree in 

 being finelj', often flexuously, striate, with occasional large spines projecting at right 

 angles from the surface. There are from 15 to 18 or more strias in the space of 10 

 millimeters. The hinge line is nearly as wide as any portion of the shell in front, the 

 ears large, quadrate, and marked by coarse wrinkles, which are sometimes continued 

 more or less strongly over the visceral portion of the valves. This is especially the 

 case in the dorsal valve. 



The largest example noted must have had a transverse diameter of nearlj^ 65 milli- 

 meters with a length of nearly 80 millimeters. An average specimen of the larger 

 sort would measure about 45 millimeters across. 



This is the form to which Norwood in 1854 gave the name Productus prattenianus. 

 These shells differ materially from d'Orbigny's figures of Productus cora, but it is 

 almost certain that his figures are altogether misleading, and the resume of the 

 matter given by Waagen is a very plausible argument for considering that the South 

 American form is the same as that for which Prodicctus praMenia/mos was proposed. 

 It has therefore been found necessary to employ the earlier published but less 

 perfectly defined term. 



Productus cora is rare in the Rico formation.- Four localities have furnished 

 each a specimen. So far as the collections at hand indicate, the form which is found 

 in the Rico does not differ materiall}- from that occurring in the lower formation. 



Locality and horizon.— 'Sn.n Juan region (stations 2196, 2196a, 2200, 2204, 2205, 

 2208, 2209, 2210, 2213, 2216, 2219, 2221?, 2222, 2233, 2239, 2248, 2331, 2332, 2.334, 

 2885, 2340, 2841, 2342, 2344); abundant in the lower, middle, and upper portions of 

 the Hermosa formation, rarer in the Rico formation. Crested Butte district (stations 

 2300, 2302, 2306, 2313, 2317); Weber limestone and Maroon formation. Leadville 

 district (stations 2254, 2257, 2259, 2268, 2270?, 2271, 2275. 2281); lower and upper 

 portion of the Weber formation, and base of the Maroon formation (?). Ouray 

 (stations 2194, 2195a) ; Hermosa formation. 



Productus pertenuis Meek ? 



1866. Productus cancrini. Geinitz, Carb. und Dyas in Nebraska, p. 54, tab. 4, fig. 6. (Not P. cancrini 

 de Verneuil, 1843.) 

 Upper Coal Measures: Nebraska City, Nebr. 

 1872. ProduHus pertenuis. Meek, U. S. Geol. Surv. Nebraska, p. 164, pi. 1, figs. 14a-c; pi. 8, figs. 9a-d. 

 Upper Coal Measures: Nebraska City and Brownville, Nebr.; Grasshopper Creek, 12 miles west 

 of Leavenworth and Atchison, Kans. 



