ART. 12 CLASSIFICATION OF CONODONTS ULRICH AND BASSLER 8 



conclusive paleontologic d;itu concerning the age relation of the 

 various Devonian and Mississipplan black shale formations. In 

 other words, none of the Genesee and Portage conodonts from New 

 York localities could be accurately identified in the equally large 

 conodont faunas from the Ohio black shale in Ohio, the major 

 upper part of the New Albany black shale in Kentucky, or in the 

 Chattanooga shales in East and Central Tennessee and Alabama. 

 On the other hand numy of the New York Devonian species of 

 conodonts were satisfactorily recognized in unquestioned Devonian 

 black shales that underlie 400 to 500 feet of Chattanooga shales in 

 southwestern Virginia. Some of the same and other New York 

 species are represented also in the locally developed basal parts of 

 the New Albany shale of Kentucky in which they are associated 

 with such other typical DeA'-onian fossils as Schizoholvs truncata 

 (Hall). In so far then as the evidence of the conodonts is con- 

 cerned, the post-Devonian age of the Chattanooga and Ohio shales, 

 as long advocated by the senior author, seems conclusively estab- 

 lished. 



Two faunas, one of Upper Devonian age and the other from the 

 basal Mississipplan rocks, were selected for description at the 

 ])resent time; first, on account of the abundance and excellent 

 preservation of the specimens; second, because the many species in 

 these faunas gave us the opportunity to test the validity of our 

 new genera; and, lastly, the two horizons represented made it 

 possible to determine the value of the conodonts as index fossils. 

 The Devonian fauna was obtained in the black Rhinestreet shale 

 of the Portage group at Shaleton, Erie County, N. Y., a small station 

 on the Buffalo and Lake Erie traction line about 14 miles southwest 

 of Buffalo. Here, according to Mr. Raymond R. Hibbard, an 

 enthusiastic paleontologist of Buffalo, who collected the specimens 

 and generously presented the United States National Museum with 

 ample material for study, the Rhinestreet shale is about 12 feet 

 thick and almost barren of fossils except in the basal 10 inches, 

 where the conodonts abound. Mr. Hibbard's efforts in promoting 

 the study of the conodonts are to be commended, and we have had 

 pleasure in naming the fine new genus HihhardeJJa in his honor. 

 The second fauna was collected by the writers some j-ears ago at 

 Mount Pleasant, Tenn., in the Hardin sandstone, a thin more or less 

 phosphatic basal sandstone forming the introductory member of the 

 Mississippian-Chattanooga black shale in central Tennessee. 



As noted above, the conodonts liave not been employed in detailed 

 correlation to the extent that they deserve because of erroneous 

 impressions as to their variability and long range. We believe that 

 if carefully prepared and discriminated, they will be found as 



