IN OSS SNES eae MONEE CIAL Ne 
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184 Cincinnati Society of Natural History. 
this drainage system, vast internal lakes were formed by the elevation 
of the western mountain chains, which overflowed and drained them- 
selves across the central part of the continent, and produced, as we 
will see, in the sequel, all the phenomena of the drift. 
As heretofore, we will follow the historical and chronological order 
_ of discovery as far as practicable. 
In 1817, Dr. Daniel Drake,* of Cincinnati, wrote an essay upon the 
alluvial and drift formations of Ohio and the surrounding country. 
The letter was not published, however, until 1825. He supposed that 
the gravel and sand which spreads itself over the western part of Ohio, 
and is not found over eastern Kentucky, is the result of an inundation, 
having its origin north of the lakes, and that the large bowlders and 
blocks of stone, distributed over the country, were transported by large 
fields of ice and icebergs, which floated from the arctic regions during 
this inundation. He said, the ice to which they were attached could 
not of course pass a certain latitude ; and from the great increase of 
these masses as we advance toward the north, it would seem that 
many of the icebergs suffered dissolution long before they arrived at 
this locality. 
In 1820, Caleb Atwater} stated, that an arrow-head was found in 
the alluvium, when digging a well at Cincinnati, 90 feet below the sur- 
face ; that a human skeleton was found in the alluvium at Pickaway 
plains, 173 feet below the surface, that could not have been interred 
by human hands in that position ; and he figured and described a 
human skull of a very low grade, which was found nine feet below the 
surface, in such a position as to suggest its contemporaneity with the 
drift era. : | 
In 1825, Sayers Gazley{ found fossil wood in Hamilton county, 
Ohio, below the gravel, and intermixed with it and bluish earth, at 
depths from 10 to 40 feet below the surface, and apparently where the 
trees had originally grown. 
In 1838, Prof. James Hall§ observed the indications of diluvial 
action, in western New York, in the accumulations of gravel, sand, 
pebbles and bowlders of all dimensions strewn over the surface. In 
some places slight scratches were observed on the rocks, while in others 
they were numerous and deep, often extending for several feet, and in 
* Trans. Am. Phil. Soe., vol. ii. 
+ Am. Jour. Sci. and Arts. 
t Ibid. 
2 Geo. Rep. N. Y. 
