FAUNAL EVIDENCE AND CORRELATION. 227 



ated with this species White cited Splrifer rocky montanus Marcou, Spiriferina 

 octopUcata Sow., Sjplrigera suhtillta Hall, liemijyronites crenistria Phillips, and Axo- 

 ■phyllum radh White and St. John, and he refers the whole to the age of the Coal 

 Measures.* The list of species identified by me is as follows: 



OELENTERATA. 



Zaphrentis-? sp. c. 



BRACHIOPODA. 



Orthothetes iniequalis. 

 Spirifer centronatiis. 



Spirifer sp. b. 

 Seminula humilis? 

 Eumetria woosteri. 



GASTEROPODA. 



Pleurotomaria? sp. b. 



With material which is not only scanty but preserved in the fashion that this is, 

 the same precision is not attainable as in more abundant normal examples, and it will 

 be noticed that I have departed from White's identifications in raan}^ instances. My 

 reasons for doing so are stated in the description of species in each case. Considered 

 apart from the form described as Emnetria ir(X)f!terl, the evidence is not conclusive; 

 but the absence of characteristic Coal Measure forms and the presence of such as 

 Spirifer centrtinatns and Seminula humilis directs a decision favorable to the Lower 

 Carboniferous age of the fauna. 



Euvtetria 'wooxteri, although its generic position on internal and strictlj' generic 

 characters can not be ascei'tained, is a form to which nothing similar has yet been 

 recorded from Upper Carboniferous strata, but which is very closely allied to several 

 species occurring some in the Kinderhook and others in the St. Louis and Chester 

 divisions of the Lower Carboniferous, and forming together a group of shells 

 peculiarlv Mississippian in expression. It may be that subsequent discoveries will 

 enlarge the range of Euinetrin and the other tj'pes involved, but at present at least 

 the evidence, coincident in every species, indicates the Lower Carboniferous age of 

 this fauna. I think, too, that the age indicated is basal Lower Carboniferous. 

 Eumetria iixuMerl appears to be on the whole more closelj' related to the Kinder- 

 hook than to the Chester species of Euvietria, and I am disposed to believe that it 

 will prove a sjMionym of Eumetria altirostris. Strands of evidence more or less 

 teiuious jjroceeding from the species Orthothetes insequalis? , Spirifer centronatiis, 

 and Seminula humilis all tend to the same conclusion, and justify the provisional 

 reference of this fauna to a position somewhere in the Kinderhook or the Osage divi- 

 sion of the Mississippian. Most of the species which I have identified are found also 

 in the Millsap limestone farther south or in the Leadville limestone atLeadville. It 

 seems very likely, therefore, that the rock from which these impressions were made 

 was derived from the same horizon that furnished the fossils from those localities. 

 The sharpness of the detail of the impressions and their nature as such even suggests 



'lU. S. Genl. Geog. Surv. Terr., Cont. to Pal., Nos. 2-8, author's edition, ,TnIy, 1880, p. 1.34. 



