Smitli.] -08 [Oct. 2. 



Siuklles. The siphonal l()])es are lono-, narrow, and pointed ; the first 

 lateral broadly pointed, and on the nmbilical slioulder is another shallow 

 lolie, broad and pointed. Tlie siphonal saddle is narrow, with the usual 

 indentation at the end ; the first lateral saddle is broadly rounded and 

 deep, the second lateral saddle shallow and inclined to be pointed. The 

 inner lobes ai"e three in number, a long, narrow, pointed antisiphonal 

 lobe, and a pair of sliorter, pointed lateral lobes ; the four internal sad- 

 dles are rounded. The figures on PL xxiii, Fig. 5, a and h, show the 

 sutures to be characteristic of Gnstriocer'as ; but the second lateral lobe, 

 while on the i;mbilical shoulders, is plainly visible from the outside. 

 Thus the species might be referred to the genus Paralefjoceras of Hyatt ; 

 but it has onlj' nine lobes and nine saddles, while Paralcgoceras has 

 eleven of each. For a discussion of this see p. 256 under description of 

 the genus G(fstriocer<(s. 



Surface Characters. — The shell is preserved on only a small portion of 

 the specimen, but the cast shows the generic and specific characters 

 quite as well. Obscure and somewhat doubtful constrictions were 

 observed, but the preservation is such that their interval could not be 

 ascertained. The umbilical shoulders are marked with rather weak 

 nodes or ril)s, whicli on the outer whorls reach uj) nearly to the 

 abdomiinil shoulders ; on the young shell they are relatively much 

 stronger. 



Affinities. — Gastrioceras hrainieri belongs to the group of 6r. lister l 

 ^lartin, G. jossee Verneul, and G. maricmum, all characterized by trape- 

 zoidal cross-section, umbilical ribs, pointed lobes and rounded saddles, 

 and evolute whorls. From the above-mentioned species G. hraimeri 

 differs in the narrowness of its whorls, and wide, shallow umbilicus ; it 

 seems to depart further from the Glyp]iiocer(ts stock than any other 

 Carboniferous species of the genus Gastriocrrax. 



Occnrrence. — Gastrioceras hranneri was found along with Pronorites 

 eyclolohiis Phillips, var arkansiensis J. P. Smith, in Arkansas, on Pilot 

 mountain, Carroll county, three and a half miles southwest of Valley 

 Springs, in 17 N., 19 W , section 18, northeast corner, in the Lower Coal 

 ]Measures, so-called "Millstone-Grit" (AlO of Prof. H. S. Williams' 

 section). About fifty-five feet below this horizon lie coarse, reddish 

 brown, fossiliferous limestone supposed to be the Chester beds of the 

 Lower Carboniferous. 



The tj^pe, for the use of wliieh the writer is indel>1ed to Prof. H. S. 

 Williams, is the property of the LT. 8. Geological Survey (National 

 Museum), catalogue number Sta. 1275. 



Gastrioceras (ih)hidosiim^\vi'\\;\\\i\^\i)Y\\\v\\. PI. xviii. Figs. !-(>. Gonia- 

 titesglohulosiis Meek and Worthen, J'roc. Acad. Nat. Sri. Phila.. 1800, 

 p. 47. Goiriatitcs (jlobulosas Meek, Geol. Sin'r.IUiitois, ii, p. 300, PI 

 XXX, Fig. 2. Gastrioceras (jlobulosam M. and W., sp , A. Hyatt, 

 P-oc. Boston Soc. Nat. Hist., 1888, p. 827. 



Tliis species resembles Gmtiatit-s (Gastrimu ra.s) hai/lmu /i.si.-< ^VIlite, of 



