GEOLOGY OF OHIO 



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. 



