84 The American Geologist. August, 1898 
Kentucky. The base of them, therefore, would have had an 
elevation of 1,800 feet on the crest of the anticline, supposing 
it were in existence. The base of the knob in Devonian Black 
shale has an elevation of 1,000 feet. The formations between 
this and the top of the Lexington limestone will add up about 
800 feet, making 1,600 feet for the thickness of the strati- 
graphic sequence between this limestone and the base of the 
Coal Measures. Place this series upon the top of the denuded 
blue grass dome and we have at least 2,600 feet as its restored 
bight. To this must be added whatever thickness of Coal 
Measures went over. 
Of course it is not unlikely denudation has been accom- 
plished pari passu with elevation and these extreme bights 
have never been attained. It is also possible the arch in its 
present condition is of recent geological development and may 
have been formed subsequent to much of the denudation. 
There seems to be a striking parallelism recorded in the 
history of the Ozark and Cincinnati uplifts. The cycles of 
erosion in each seem to have been contemporaneous, affect- 
ing indeed the intervening country as well. The differences 
seem to have been more in the extent of the vertical move- 
ments than in the time of them. The lowest strata exposed 
in the gorge of the Kentucky river, where it crosses the crest 
of the uplift, is lowest Ordovician or Upper Cambrian. The 
most recent elevation, as recorded by the hight above the 
present channel of the old river deposits, is between 300 and 
400 feet. Had the elevation been greater there seems no 
reason to doubt but we might have had Algonkian strata ex- 
posed, just as in the Ozark uplift. 
Keyes' views that the last uplift took place in Tertiary 
times are endorsed by Marbut, Davis, Griswold and others. 
Campbell, who studied the gravels, sands and clays covering 
the uplands in the vicinity of the Kentucky river where it 
emerges from the Eastern coal field, considers them deposits 
of an upland river thrown down where its gradient changed 
upon entering a base-leveled plain. He favors the Tertiary 
age of these deposits and provisionally colors them as Neocene 
on the map. This would assign to late Tertiary the date of the 
last upward movement in this region. 
In the light then of all the evidence cited: — that afforded 
