CHOmOGY OFF ©O.EnO. 
CHAPTER XXX. 
SURFACE GEOLOGY. 
In Ohio we have no geological formations intervening between the 
Carboniferous and the Quaternary, and have, therefore, no representa- 
tives of the Permian, Triassic, Cretaceous, or Tertiary systems. The 
reason of this is simply, that about the close of the Carboniferous age 
the Alleghany Mountains were raised, carrying up all the area lying 
between the Mississippi and the Atlantic. From that time to the Qua- 
ternary no part of this region, with the exception of the southern mar- 
gin, was ever submerged, and, therefore, no deposits were made on it 
during the ages I have enumerated. West of the Mississippi the land 
has been often and long below the ocean level since the epoch of the 
Coal Measures, and there all the newer formations are well represented. 
The materials which accumulated during the Quaternary are beds of 
clay, sand, gravel, and bowlders, which have received the name of Drift, 
because they are generally foreign to the localities where they are found, 
and have been transported (drifted) sometimes hundreds of miles from 
their places of origin. 
The Drift phenomena of Ohio constitute a marked feature in its geol- 
ogy; one, indeed, more apparent and conspicuous to the superficial ob- 
server than any other, inasmuch as the Drift deposits cover nearly all 
parts of the State, and frequently conceal the underlying rocks so as 
to completely mask the fundamental geological structure. Perhaps no 
other State has so complete a series of these deposits, or a more legible 
record of the remarkable sequence of events which gave character to this 
chapter in geological history. The Quaternary system deserves, there- 
fore, and will receive in this report, as full and thorough an exposition. 
as our limitation of space will permit. Like most of the formations 
