m.f Mo 1 



Wo ly .loul't tliat the Minnesota specimens above described really 



belong to Billinj-' V- '..<'""" suptrba. They agree exactly with his figures and 

 description except th:it we see nothing of the "obscure carination" which he says 

 "runs from the apex to tin- margin on one side." Perhaps itisan abnormal feature. 

 n<-hi'lli< minnesottnsis, Walcott's description, in the absence of figures, is 

 too indefinite for identification.' Still we do not think it likely that his types, 

 which we sought to see but. failed, are distinct from the specimens here referred to 



Nor do we believe thsit they are strictly congeneric with his ('. 

 'i. the type of his proposed genus ConchoptHis. (See ante page 323.) 



and loo: - n.-t Riv.-r ifr.mp, Cmnnon Fall*, MlnncsoU. Walcott's locality for his 



tMMteiw '..ur mil.- innoti Hlv.-r, Minn." Kllllnga' type Is fr.mi tin- 



HI*-. mectooeat Pftu<|Uctt<-H rapid* <>n th.- Ottawa rlv.-r. 



OoUteUont. Oootoglcal and Natural Hi*t >f Minnesota: \\ II. S.-..(l.-lil; K O. Ulrlch. 



Mtufum Rrgitter, N<H. 33M, 73fiO and 7490. 



ScKNKI.f.A IfAONIKICA. H. up. 

 I'l.ATE I.XX.XH. KIOS. 7-9. 



if this -pecies we have only a single specimen which was found in norijition 

 with the preroiling species at Cannon Falls. It seems to have had surface markings 

 liki- X. .ni#rli, ;inl we believe it is closely related to that species. Hut the hight 

 of the shell is so much greater that we cannot do otherwise than regard it as 

 specifically distinct. Comparing other features we find that the aperture also is 

 more arched and the whole shell more compressed laterally so that the outline 

 from above is decidedly elliptical instead of subcircular. length 76 mm.; width 

 58 mm.; hight alwut 75 mm. The specimen is imperfect at the apex. 



ittty. Stones River group, Vanuxemla bed, Cannon Falls, Minnesota. 

 logical and Natural History Survey of Mlnn.-sota. 

 Htuntm Reffitter, No. 



SCKNKLLA BKIXtlTKNSIS, M. ftp. 

 VI. \ TK I. \l. Ih.-. B and M. 



II exceeding mflium -i/.c, ontn-iMy conical, the hight less than one-half of the 

 smallest iliameter; apex snbcentral; aperture nearly or .jiiito horizontal, somewh.it 

 irregularly subcircuUr. Surface of ra-t -h.wing fine radiating stria-, about ten in 

 5 mm., over the marginal portion. Muscular imprints occupying the greater part of 

 the inner half, apparently divi.le.l into four sets, each consisting of three or four. 

 scarcely distinguishable, coherent scars. Length -JS mm.; width -jr. mm.: hiyht 

 1 <>." mm. 



Wl^.u-. dwerlpUoa read* M follow*: - Shell obtawly eoaleml. (MM ^ ptlcal: api ciwotn 



dlV>rMtladlTldaki<:hlfbt<f^klf UCTMlM4UlMw. Hballo. unduUt not to 



of tk toll not 



