392 PALAEONTOLOGY OF ILLINOIS. 



G. gphmrwus, Martin, agrees more nearly in form with our shell, but has a 

 much smaller umbilicus, while its septa are entirely different The septa of 

 G. diadema, of Goldfuss, are very similar to those of our species, but that 

 species has also a smaller umbilicus, and is much less ventricose than ours. 



For the use of the very fine specimen from which our large outline cut No. 

 38 was made, we are indebted to Prof. B. Daniels. It is much larger than the 

 typical specimens found in this State, and has the whorls a little less angular 

 on each side, though we believe it belongs to the same species. Prof. Daniels 

 obtained it from a clergyman in Kansas, who could give no information iu 

 regard to the locality from which it was obtained, beyond the fact that it was 

 found in Eastern Kansas. It shows faint traces of obscure nodes on the obtuse 

 lateral angles of the whorls. 



Although our figures on plate 30 show apparently the average size of this 

 species at the Springfield locality, we have before us a fragment from there, 

 indicating a size of nearly half that of the Kansas specimen. 



Locality and position : Upper Coal Measures, Springfield, Illinois. Also 

 Eastern Kansas. 



Goniatites iowensis, M. and W. 



PL 30, fig. 3 a, 3b, 3c. 



Goniatites iowensis, Meek and Worthen, October, 1860. Proceed. Acad. Nat. Sci., 

 Philad., p. 471. 



Shell attaining a rather large size, discoidal or nearly flat 

 on the sides, and narrowly rounded on the dorsum. Umbili- 

 cus rather shallow, about one-half as wide as the breadth of 

 the outer whorl from the ventral to the dorsal side, showing 

 apparently about one-third of each inner whorl. Volutions 

 increasing gradually in size, but slightly convex on the sides, 

 nearly twice as broad from the ventral to the dorsal side, as 

 the transverse diameter, and profoundly grooved within for the 

 reception of the inner whorls ; aperture, as near as can be 

 determined from a section of the whorls, narrow-subovate, 

 deeply sinuous on the ventral side. (Surface unknown.) 



reversed the usual mode of describing the sinuosities of the septa. That is to say, he 

 has described the lobes as sinuses, and the sinuses or saddles as lobes. 



