10 PROCEEDINGS OF THE NATIONAL MUSEUM. 



A><p)d<>i><>r<i eccentriea^ and BatoxtoiiKi '/((ine.st hyq particularly abundant 

 and characteristic. 



McMicken. — The upper third of the Eden consists of about 60 feet 

 of highly calcareous and extremely fossiliferous shales and limestones 

 holding" the hvyoy.oan I)(l<n/<'ll(i iih'tcJu in g'r<nit abundance. Good 

 exposures occur along McMicken avenue, Cincinnati, Avhence the 

 name for the division. 



l^alriuiio. — Nickles\s divisions of Mount Hope and Fairmount, 

 although useful for detailed work, are so closely related faunally and 

 distinguished with such difficulty that for mapping purposes the term 

 Fairview, from Fairview Heights at Cincinnati, is here proposed to 

 embrace both. The Fairview formation is about 100 feet thick, and is 

 the equivalent in part of the '"'' Hill quarry beds" of Professor Orton, 



MeMUkin. — The Bellevue, Corryville, and Mt. Auburn members 

 are closely related and not of sufficient importance to be mapped 

 separately. The three are here recognized as members of the new 

 formation, the McMillan, from the street of that name at Cincinnati, 

 along which the 85 feet of strata comprising this formation are fairly 

 well exposed. 



Arnhei)!). — Nickles's term Warren being preoccupied, the new name 

 Arnheim was proposed'^ for this division, which here is considered a 

 part of the Richmond group rather than of the Lorraine, as hitherto 

 placed. Excellent exposures of these strata are found in the vicinity 

 of Oregonia and Lebanon, Ohio. 



DISCUSSION OF SPECIES IN ALPHABETICAL ORDER. 



In manj' cases the James type lots contain such a variety of speci- 

 mens, or are so involved in other respects, that it has seemed best to 

 discuss in alphabetical order not only Mr. James's own species but 

 also those of which his forms have proved to be synonyms. In order 

 to facilitate reference to any particular form, this discussion of species 

 is followed by an index. The synonymy of some of the species is so 

 extended that for the sake of space, only that part of it essential to 

 this paper is given. The complete synonymy is presented in Bulletin 

 U. S. Geological Survey, No. 178. 



ALECTO NEXILIS James, 

 ^/erto 7(ya:///.s James, Iiitr. Catal. Foss. Cincinnati (ironp, 1S75, ji. 8. 



Original de-seription. — "Pol3'zoary attached to branches of coral, 

 consisting of thread-like tubes anastomosing closel}', resembling fine 

 network, with 7 or 8 meshes in the space of a line; the little circular 

 mouths are raised and at iri-egular distances, varying from one-eighth 

 to one-sixteentii of a line apart. 



•'The typical specimen of this species is spread over a small, 



«Foei-ste, Science, XXII, 1905, No. 553, p. 151. 



I 



