74 



Report of the State Geologist. 



typical examples of that genus both in whorl section and in the course of the 

 suture, but in the development of both of these features there is certainly a 

 wide difference between this species and Maritic. intumescens. Thus the great 

 breadth of whorl, which in Mantic. fasciculatum continues through fully four 

 volutions, is hardly more than suggested in the early stages of Mantic 

 intumescens, and the exceedingly large acuminate ventral lobe of Mantic. 

 fasciculatum which is unmodified up to the fourth volution is remarkable, as 

 this primitive lobe is soon modified in typical Manticoceras and at no time has 

 such a degree of prominence. Whatever the significance of these differences 

 may prove to be, the species must, for the present, be left with this genus. 



Occurrence, Manticoceras fasciculatum lias been found only in the Styliola 

 limestone, on Canandaigua lake and in the village of Middlesex, Yates count}-. 



Manticoceras nodifer, Clarke. 



Plate VI, Figs. 24-26. 



1885 Goniatites nodifer, Clarke, Bull. U. S. Geol. Surv. No. 16, p. 21. 



This species was based upon a few small shells from the Styliola liine- 

 stone which were described as follows: "Shell umbilicate, body-whorl 

 expanding rapidly outward, its width at the stoma being two and one-half 

 times that at the beginning of the volution, compressed laterally, sloping 

 gradually to the dorsum [venter] which is rounded; widest on the inner 

 margin where it falls away abruptly to the inner whorls. The umbilicus 

 shows five whorls which overlap one another in such a way as to leave each 

 preceding one exposed for about one-fifth of its width. Diameter of the 

 normal full grown shell 14 mm., of which the umbilicus covers five mm. 

 Suture: Dorsal [ventral] lobe short, lanceolate; dorsal [ventral] saddles 

 small, rounded and sloping slightly toward the umbilicus; outer lateral lobes 

 somewhat narrower than the dorsal [ventral] saddles but of the same length; 

 lateral saddles broad, rounded, twice as long as the dorsal | ventral] saddles, 

 and distinctly sloping toward the umbilicus. Inner lateral lobe short, rounded 

 and the ventral [dorsal] saddle small and indistinct. The inner whorls are 

 edged with strong nodes, which may be the protruding ends of ridges passing 

 across the whorls. These number from 12 to 16 for each whorl, but become 

 fainter on the younger [ later | whorls and are hardly distinguishable on the 

 last volution. No other marks of ornamentation are visible." 



The distinguishing features of this species .-ire its narrow and deep 

 umbilication and nodose inner whorls. Among the material acquired since 



