1896.] '^t)0 [Smith. 



genus to embrace tlioso forms with two lateral lobes and a "suspen- 

 sive" lobe on the umbilical shoulders. Hyatt, in the Geological Survey 

 -of Texas, Second Annual Report, 1891, p. 355, emended the genus Paral- 

 ^goceras to include those forms with the second lateral lobe on the 

 iiimbilical shoulders, and he included in it GastiHoceras russiense Zweta- 

 jew. But the Russian species has the suspensive lobe on the side and 

 has onl}' nine lobes in all, and thus ought to remain in the group char- 

 acterized as Gastrioceras. 



In the Fourth Annual Report of the Geological Survey of Texas, 1893, 

 p. 474, Hyatt has described under the name of Paralegoceras iowense 

 Meek and Worthen, a goniatite from the Bend Formation of Texas. 

 But the lobes are not exactly like those of the Iowa Coal Measures spe- 

 cies, the third lateral saddle is on the umbilical shoulders, and the 

 young shell is marked with ril)s which form well-defined tubercles, even 

 on the older shell. These difierences were explained by the supposition 

 that the Texas specimen was the young of Paralegoceras iowense, and 

 might thus naturally show them. But since the Arkansas specimen is 

 a young one and still shows all the characteristics of the adult, it 

 I)ecomes very likely that the Texas specimen belongs to another species. 



There is also another reason why this is probable. The Bend Forma- 

 tion is called Coal Measures by the Geological Survey of Texas, but its 

 fauna seems to be identical with that of the Fayetteville shale of 

 Arkansas, which belongs to the Lower Carboniferous, and probably to 

 the Warsaw or St. Louis division. Species that are almost certainly 

 identical with Glyphioceras incisuni Hyatt and G. cumminsi Hj^att have 

 been collected in the Fayetteville shale of Arkansas. And since these 

 goniatites have unusually only a limited stratigraphic range, it is very 

 probable that the species from the Bend Formation is not identical with 

 that from the Coal Measures. 



Occurrence — A single specimen oi Paralegoceras ioicense was found in 

 Arkansas, in the Lower Coal Measures of Conway county, 5 N., 16 W., 

 section 17, near centre of north half. The species was originally 

 described from the Coal Measures of Iowa and since then has not been 

 cited from any other locality up to the present occurrence, unless the 

 Texas species of Hyatt should be the same. There can, however, be 

 very little doubt that Goniatites misso uriensis Miller and Faber {Journ. 

 Cincinnati Soc. Nat. Hist., Vol. xiv, p. 164, PI. vi. Fig. 1), from the 

 Upper Coal Measures of Missouri, near Kansas City, is identical with 

 Paralegoceras iowense Meek and Worthen. 



Family Prolecanitidce Hyatt. 



The Prolecanitida', as originally described bj^ Hyatt,* included cer- 

 tain elements that do not belong to this stock ; but, as revised by Kar- 

 pinsky,f it forms the most perfect genetic series known, radiating from 



* Proc. Boston Soc. Nat. Hist., Vol. xxii, p. 331. 

 ■^Ammoneen der Artinsk-Stufe, pp. 41-45. 



PKOC. AMER. PHILOS. SOC. XXXV. 152. 2 H. PRINTED DEC. 9, 189G. 



