MEDINAN, NIAGARAN, AND CHESTER FOSSILS 
39 
Nothing is known of the fossils of the Plum Creek clay shale, 
at least within the area of its typical exposure. Farther north, 
at the Rose Run quarries, east of Owingsville, Kentucky, a 
considerable fauna once was exposed in strata overlying the iron 
ore horizon. This fauna never was collected but it contained 
species resembling Clathropora cUntonensis, Strophonella day- 
tonensis, and other species resembling forms known in the Brass- 
field limestone, but at the time this fauna was examined in the 
field it was regarded as sufficiently distinct from the typical 
Brassfield to be regarded as probably of Niagaran age. 
The Brassfield limestone is regarded as equivalent to part of 
the Medinan section in the Niagara Falls area of New York 
and in southern Ontario. 
At the base of the Brassfield limestone, in the quarry imme- 
diately north of Lawshe, in Adams county, Ohio, Platymerella 
manniensis Foerste was found in a thin horizon only a few 
inches thick. ^ This occurrence is of interest because the same 
species occurs at a corresponding horizon in western Illinois and 
eastern Missouri." At these western localities the Platymerella 
horizon is underlain, in descending order, by the Essex, Edge- 
wood, and Girardeau limestones. Recently fossils have been 
found in argillaceous strata underlying the typical Brassfield 
limestone, in Montgomery county, Ohio. These beds are of 
Silurian age and may correspond approximately to one of the 
western horizons, presumably to the Edgewood limestone, as 
far as may be determined from the meager data secured so far. 
In that case they belong beneath the Platymerella horizon. 
This lower Silurian horizon in Ohio may belong beneath the 
argillaceous horizon for which the name Belfast bed was pro- 
posed 27 years ago."^ At the time this name was proposed two 
Silurian species were known from the top of the Belfast bed, 
Haly sites catenulatus, and a form of Orthis flahellites with 44 
2 Foerste, A. F., The Kimmswick and Plattin Limestones of Northeastern 
Missouri: Denison Univ. Bull. Sci. Lab., vol. 19, 1920, pp. 223, 224. 
® Savage, T. E., Stratigraphy^ and paleontology of the Alexandrian series in 
Illinois and Missouri: 111. State Geol. Survey, Bull. 23, 1913, p. 36 of reprint. 
4 Foerste, A. F., The Middle Silurian rocks of Ohio and Indiana: Jour. Cin. 
Soc. Nat. Hist., vol. 18, pp. 163-166, 1896. 
