88 CARBONIFEROUS AMMONOIDS OF AMERICA. 



Gasteioceras excelsum Meek. 



PI. XVI, %. 2; PL XXVIII; PI. XXIX. 



1866. Goniatites glohrdosuii (pars), Meek and Worthen, Geol. Surv. Illinoi.s, Vol. II, 



p. 390, fig. 38 (not PI. XXX, figs. 2 a-c). 

 1876. Goniatites gloh^dosus var. excelsus, F. B. Meek, Bull. U. S. Geol. and Geog. 



Surv. Terr., Vol. I, No. 6. p. 44.5. 

 1896. Gastrioceras excelsum^ J. P. Smith, Proc. Am. Philos. Soc, Vol. XXXV, 



p. 260, PI. XVII, figs. 1 a, b, c. 



This is the largest known species of Carboniferous ammonoids. A 

 specimen from Osage, Kans., now deposited in the United States National 

 Museum, has a diameter of 11 inches, and is entirely septate, so that the 

 full size, with the complete body chamber, must have been several inches 

 more. Shell globose, with depressed helmet- shaped whorls, and abruptly 

 rounded umbilical shoulders. Width of whorl nearly equal to the total 

 diameter of the shell, and more than twice the height of the whorl. Each 

 whorl indented to one-third of its height by the inner volution. 



Surface apparently smooth except for obscure traces of nodes on the 

 umbilical shoulder. 



Umbilicus deep and wide, being more than one-third of the total diam- 

 eter in width. Septa of the usual gastrioceran type, ventral lobes long, 

 narrow, and pointed, divided by a broader siphonal saddle. Lateral lobes 

 longer than the ventral, and very little wider. First and second lateral 

 saddles broadly rounded. A third lateral lobe, short and funnel shaped, is 

 seen below on the umbilical .slope of tlie umbilical shoulder. This is not 

 shown in the sketch on PI. XXVIII, fig. 2, which stops at the umbilical 

 shoulder, but can be seen on fig. 1, from a photograph of the shell. Internal 

 septa unknown. 



Occurrence. — A specimen doubtfully compared by Meek with this species 

 was found at an unknown locality in the Upper Coal Measures of Kansas, 

 and figured in geological survey of Illinois, Vol. II, p. 390, fig. 38. 



This type was found in the Upper Coal Measures of eastern Kansas at 

 Osage. This is the specimen now deposited in the United States National 

 Museum. In the paleontologic collection of the Walker Museum, University 

 of Chicago, is a specimen, No. 6226, from the Upper Coal Measures of Osage, 

 Kans.; this is better preserved than the type, and has therefore been figured on 

 Pis. XXVIII and XXIX. The writer's thanks are due Dr. Stuart Weller, of 



