38 
AUG. F. FOERSTE 
farther north the collective term Alger clay is used for the con- 
tinuous clay shale section forming the upper part of the Silurian 
in Montgomery^ Bath, and most of Fleming county. In Lewis 
county, and in the northern part of Fleming county, this Alger 
clay is overlain by the Bisher member of the Niagaran. In 
Lewis county the upper part of the Alger clay contains Liocaly- 
mene clintoni and other fossils indicating relationship with the 
Clinton of Maryland and the typical Clinton of central New York, 
as exposed in the vicinity of the village of Clinton in that state. 
The Oldham limestone consists of thin limestone interbedded 
with thin clay shale. It contains very few fossils and of these 
only Stricklandinia norwoodi has been recorded. Since this 
species does not occur elsewhere than in east-central Kentucky 
it is of no service in correlation. The Oldham limestone may be 
followed lithologically as far north as the Rose Run Quarries, 
about 7 miles east of Owingsville. Farther north it can not be 
discriminated readily from the underlying Plum Creek clay 
shale, since the latter there also contains thin limestone layers, 
often in considerable quantity. 
Throughout southwestern Ohio there is a series of very white 
and fine grained limestones known as the Dayton limestone. 
In Highland and Adams counties in Ohio, and in the adjacent 
parts of Lewis county in Kentucky, this Dayton limestone lies 
immediately beneath a thick clay shale zone regarded as the 
northward extension of the Alger clay. Since the Dayton 
limestone in Flighlaiid and Adams counties contains Pentamerus 
oblongus, it is regarded provisionally as corresponding to one of 
the so-called Clinton Pentamerus horizons of the more western 
parts of New York. Possibly it corresponds approximately to 
the Walcott limestone of the Clinton as exposed in the Rochester 
area of New York. In that case the Dayton limestone forms 
the base of that part of the Ohio Niagaran which corresponds 
to the Clinton of New York, when this term is used so as to 
include the Clinton of Western New York at Rochester and as 
far west as Niagara Falls and southern Ontario as well as the 
typical area around Clinton, New York. 
