NATURAL SCIENCES OF PHILADELPHIA. 471 



On each dorso-lateral angle, there is a series of rather low nodes, about 

 twenty to twenty-two of which probably existed on each side of the entire 

 whorl. The transverse section of the whorls has a nearly quadrangular form, 

 if we regard the small ventral concavity, and the two sloping ventro-lateral 

 margins together as one side. The septa are moderately concave, and arch 

 gracefully backward on each side, while in crossing the dorsum they arch 

 less deeply in the same direction. The siphuncle is small, and located a little 

 nearer the dorsal than the ventral side. (Aperture and surface markings 

 unknown). 



Length, as inferred from the curve, about 2 inches; height about L45 inch ; 

 breadth near the aperture 0-88 inch. 



Locality and position. Sangamon County, Illinois. Coal Measures. 



Genus GONIATITES, De Haan. 



Goniatites globulosus. Shell under medium size, length and breadth 

 nearly equal, very broadly rounded on the dorsum ; umbilicus deep, less than 

 half as wide as the greater (transverse) diameter of the outer whorl ; volutions 

 more than twice as broad transversely, as from the ventral to the dorsal side ; 

 sides subangular around the umbilicus ; aperture transverse, lunate, much 

 wider than high ; (surface unknown ;) surface of internal cast slightly con- 

 stricted at intervals, as if from an occasional thickening of the lip. Septa 

 moderately distant ; dorsal lobe nearly as wide as long, and deeply divided 

 into two slightly diverging, simple, lanceolate branches ; dorsal saddle lingui- 

 form, and a little narrower than the dorsal lobe, but equalling it in length, 

 slightly contracted in the middle ; superior lateral lobe as long as the dorsal 

 saddle, but narrower, and pointed at the extremity ; lateral saddle a little 

 broader than the dorsal saddle, which it resembles in other respects. 



Length 1-18 inch; height, 1 inch; breadth at the aperture, 1-11 inch. 



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



Goniatites Iowensis. Shell attaining a rather large size, discoidal or com- 

 pressed on the sides, and narrowly rounded on the dorsum ; umbilicus shallow, 

 about one-half as wide as the breadth of the outer whorl from the ventral to 

 the dorsal side, showing apparently a little less than half of each inner whorl ; 

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

 twice as broad on a line from the dorsal to the ventral margins, as the 

 diameter at right angles to the same, profoundly grooved on the ventral side 

 r'orthe reception of each succeeding whorl; aperture, judging from a transverse 

 section of the volutions, narrow sublunate. (Surface unknown.) 



Septa rather crowded and deeply sinuous ; dorsal lobe large, considerably 

 wider than long, profoundly divided into two large lanceolate branches, each 

 of which is a little narrower above than in the middle, and abruptly contracted 

 to an acute point at the extremity ; dorsal saddle linguiform, slightly oblique, 

 a little larger than either division of the dorsal lobe, and longer than wide ; 

 superior lateral lobe infundibuliform, as long as the dorsal saddle, but not 

 more than half as wide, acutely pointed at the apex ; lateral saddle a little 

 shorter than the dorsal saddle, but narrower at the extremity ; inferior lateral 

 lobe rather shorter than the superior, particularly on the ventral side, but re- 

 sembling it in other respects ; ventral saddle shorter than the others, and 

 broadly rounded. 



Length 4-21 inches; height 3-43 inches; breadth at the aperture 1-10 inch. 



Locality and position. Alpine, Iowa. Coal Measures. 



Goniatites Lyoni. Shell attaining a medium size, compressed, discoidal ; 

 umbilicus large, or nearly twice the diameter of the outer whorl, from the 

 dorsal to the ventral side, very shallow, and showing about four-fifths of each 

 inner whorl. Volutions slender, increasing very gradually in size, compressed, 

 or about one-third deeper from the dorsal to the ventral side than the trans- 



1860.] 



