300 E. O. ULRICH REVISION OF THE PALEOZOIC SYSTEMS 



the Leipers formation. In Tennessee the latter formation rests on the 

 slightly eroded top of the Catheys, so that the local stratigraphy does not 

 afford an adequate conception of the extent of the interval beween the 

 first and second appearance of these corals. Ohio supplies the missing 

 links, these being the 550 feet of Eden shale ; the lower 300 feet of which 

 is black, represents the Utica, and is known chiefly from deep wells ; the 

 upper 250 feet being the shale which constitutes the bulk of the Eden at 

 Cincinnati. These same corals, or rather their scarcely distinguishable 

 descendants, appear once more in the Eichmond series of Ohio, Indiana, 

 and Kentucky. This last appearance is more remarkable than the second 

 for the reason that in this case the Cathey corals (including Golumnaria 

 alveolata) are accompanied by Columnaria halli, which is known else- 

 where only in upper Stones Eiver, Lowville, and Black Eiver rocks; by 

 Protarea vetusta, a Lower Trenton species, and by several types of brach- 

 iopods and ostracods commonly found in the Trenton, but unknown in 

 the often extremely fossiliferous intervening formations. 



The second faunule of the Catheys consists largely of bryozoa, with 

 smaller numbers of brachiopods, pelecypods, and gastropods, the general 

 aspect of the fauna being extremely like that of the Maysville formations 

 of Ohio and Kentucky and the Leipers formation in Tennessee. When 

 I first met this facies of the Catheys in central Kentucky I did not hesi- 

 tate to correlate it with the Maysville at Cincinnati. It seemed to me 

 that I recognized an old acquaintance in each fossil, but when the collec- 

 tions had been carefully studied I knew better; they were near—often 

 very near — relations, but never exactly the same. At the same time it 

 was learned that these progenitors of the Maysville fauna were always 

 accompanied by at least a few species that were easily distinguishable 

 from all of the Maysville fossils. These species, therefore, are pre- 

 eminently the characteristic fossils of the Catheys formation, despite the 

 fact that the most of them could not appear in a list of "standard domi- 

 nant species" drawn up according to the plan of Professor Williams. 

 His list of dominant Catheys fossils would be essentially if not exactly 

 the same as for the Maysville. 



Utican aspect of the Maquolceta fauna. — Another interesting, and at 

 first sight perplexing, reappearance occurs in the Maquoketa shale of the 

 Mississippi Valley and in the essentially contemporaneous Sylvan shale 

 of the Arbuckle uplift in Oklahoma. Aside from the molluscan fauna 

 that is limited to the basal layers and a bryozoan and brachiopod fauna 

 found in magnesian shale at the top of the Maquoketa, the fauna of these 

 two otherwise black shale formations consists almost entirely of grapto- 

 lites, phosphatic brachiopods, and pteropods. The species are nearly all 



