172 
E. R. Schejfel 
old system through the former Newark river, having a general 
direction of west-southwest. Later all this drainage was diverted , 
eastward through the present Licking valley. , ’ 
No doubt has been expressed by any writer concerning the ij 
actual occurrence of the captures indicated. The general tend- 
ency, however, has been to refer them to glacial causes. Hints 
that differential movement may have been a factor have been 
given, but nothing has been adduced to support such a theory. 
The purpose of this paper has been to emphasize the possibility 
that this may have been the controlling factor even before glacial 
times, aided also by the stratigraphy which in at least part of the 
divide area permits rapid weathering. While arguments are avail- 
able in favor of the glacial theory, yet in view of the fact that all 
the changes conform to the theoretical results following a simple 
differential movement of uplift or subsidence, it would seem that 
the latter factor should be given a more serious consideration than 
it has been accorded. 
While the problem has been treated from a localized standpoint, 
a study of Tight^s map^^ shows similar drainage changes over 
almost the whole of Ohio, including the drainage under discussion. 
Formerly this combined drainage passed northwest, now it passes 
southeast. May not the same cause have been operative in both 
instances causing the reversions; and may not the theory of differ- 
ential movement be perhaps nearer the truth than the glacial ? 
PENEPLANATION 
The hills of the western part of the county consist of rock of the 
Waverly Series. Tight in discussing the Muskingum area gives 
the Cretaceous as the probable period of base-leveling.^^ This 
time would also seem applicable to the Licking county area, 
though a later date is not improbable. If this supposition is cor-i 
rect then if these drainage changes were caused by differential ; 
movement this movement must have come between Cretaceous 
and Pleistocene times. Attempts have been made to correlate the 
rock formations of this area with those in the Allegheny Plateau 
^^Professional Paper no. 13, plate i. 
Bull. Set. Lah.y Denison Univ.^ vol. viii, pt. ii, p. 55, 1894. 
