] l>4 Tltf Ann fiat it Geologist. Feb. 1891 
not having been :i subaSrial ridge, and of its not baving suffered 
erosion, but having, on the contrary, had its existence only as a 
submerged barrier obstructing the passage of sediment-transport- 
ing currents. The separation of strata of Upper Silurian age, as 
described from Tennessee, might be explained in this way : The 
facts from the northern end of the anticlinal are readily explained 
Actual exposures of Medina are doubtfully identified at Wilming- 
ton, on the eastern side of the anticlinal, at Fair Haven, Ohio, on 
its crest, and at Hanover, Indiana, on its western side, the sandj 
strata so identified not appearing at the base of the Clinton ex- 
posures farther north in Ohio and the immediately adjacent parts 
of Indiana, at least. The Clinton crosses over from the eastern 
side of the anticlinal in northern Kentucky and Ohio, to the west- 
ern side, and is identified with certainty at Hanover. Indiana, and 
the river counties of Kentucky, just south of Hanover. Clinton 
strata, however, with different lithological characteristics, are 
mentioned farther south in Kentucky on the western side of the 
anticlinal. The Niagara strata of western Tennessee are recog- 
nized again at Louisville. Kentucky, and with different lithologi- 
cal characteristics ; also at Waldron, Indiana. In Ohio, on the 
other hand, the Dayton limestone alone could be mentioned in 
this connection, and it seems best to state that if the Waldron 
Niagara is represented in southwestern Ohio, it has unaltered lith- 
ological characteristics and definite correllation is no longer pos- 
ible for the purposes here desired. The Guelph formations, a some- 
what higher horizon, extend from Ohio across the Cincinnati 
anticlinal to central and northern Indiana. The Lower Helderberg 
strata also extend across the anticlinal in Ohio. Some of the out- 
liers of later formations, still retained near the sources of the Scioto 
and Miami, near the middle of the Ohio portion of the anticlinal, 
rise to such a hight above the crest of that part of the anticlinal 
immediately adjacent, that there is no doubt but that the strata of 
which they are formed also once extended across the axis. Those 
facts are not believed to be consistent with the existence of the 
Cincinnati anticlinal as an important barrier during paleozoic 
times. 
The striking similarity of fossil forms in corresponding fprma 
tions east and west of the anticlinal is also inconsistent with the 
existence of a significant barrier in those times. During the 
