330 The Ohio Journal of Science [Vol. XVI, No. 8, 



3. The Richmond- Albion break is regarded as impracticable 

 for the separation of major time units, because there is no break 

 there in the Anticosti series, and the break between the Lower 

 Medina (Queenstown-Juniata — Richmond) and the Upper 

 Medina (Albion — Brassfield or "Ohio Clinton") is frequently 

 obscure. 



4. The later Maysville seas were notably restricted, and 

 at the close of the Maysville were drained away. The Arnheim 

 shale (earliest Richmondf) was deposited over the gently 

 warped surface of the interior, and the break is shown in 

 overlap" irregularities in sequence and thickness of deposits. 



This break is correlated with larger and more distinct breaks 

 in the Appalachian and other regions. 



These points willbe briefly discussed in order. However, 

 it may be said here that the writer holds that in so far as crustal 

 warpings and their consequent changes in land and sea relations 

 are concerned, they are best reflected in the faunal changes which 

 take place. The less local and more wide-spread the movement 

 the greater the effect upon the life of the time. It is held that as 

 a general proposition slight oscillations have but little repressive 

 effect upon the forms of a given area, and but few new forms 

 are introduced, while broad movements are likely to result in 

 decided repressions on the one hand, and radical innovations on 

 the other, and actual physical records of diastrophism might well 

 be lost, obscured or inaccessible, and yet be reflected in a very 

 positive and far-reaching way upon the life of the times. 



1. In comparing the life of the Maysville with that of the 

 Richmond, faunal lists have been based upon the recently 

 published Bibliographic Index of American Ordovician and 

 Silurian Fossils.* This has been modified by data collected 

 by the writer and by Prof. S. R. Williams during seven seasons' 

 systematic field work in the disputed strata. The lists include 

 fossils from the Maysville of the Cincinnati dome, of New York 

 and of Canada, and Richmond fossils from the Cincinnati 

 region, the upper Mississippi Valley, and from the Fernvale 



t In ascending order the subdivisions of the Richmond are commonly given 

 as Arnheim, Waynesville, Liberty, Whitewater, Elkhorn, and Belfast. The 

 Saluda is the western shallow-water equivalent of the upper half of the White- 

 water and all of the Elkhorn. 



* R. S. Bassler, Bull. 92, U. S. Nat. Mus., 1915. 



