HGS The American Geologist. Decombor, 1896 
all of the divisional lines that have been selected by different 
authors for different localities can and ought to be recognized. 
There should even be added one or two more in order to ex- 
pi-ess more nearly the true relations of the strata of the two 
series to each other. Such a classification will be the subject 
of the next paper. 
ORIGIN OF THE HIGH TERRACE DEPOSITS OF 
THE MONONGAHELA RIVER.* 
By I. C. White, Morgantown, W. Va. 
At the Minneapolis meeting of the A. A. A. S., in 1883, the 
writer presented a paper before Section E in explanation of 
the terrace deposits along the Monongahela river, as well as 
those along the old and abandoned Teazes valley, which ex- 
tends from the Great Kanawha at St. Albans, along the C. & 
O. R. R. to the Ohio river at Guyandotte. 
In that paper the origin of these deposits was referred to 
the hypothetical glacial dam in tlie region of Cincinnati, evi- 
dence for the* existence of which had just then been published 
by Prof. G. F. Wright, of Oberlin, Ohio. 
Continued studies of the river between the Great Kanawha 
and the Monongahela have still led the writer to refer the 
terrace deposits of the latter river to a glacial dam, but not to 
the one which Prof. Wright believes existed at Cincinnati. 
It is now pretty surely established, through the work of 
Carll^ Spencer, Hice. Foshay, Chamberlin, Leverett, and oth- 
ers, that the Monongahela, lower Allegheny, and upper Ohio 
waters drained northward into the lake Erie basin in pre-gla- 
cial time. The great ice-field which covered northern Ohio 
and Pennsylvania, and descended southward nearly to the 
Ohio river at Rochester, or Beaver, Pa., would, of course, ef- 
fectually stop the northward drainage of this pre-glacial river, 
and impound the accumulating water into a vast lake-like 
reservoir, until it lilled up to the level of any divides that 
might lead the surplus water across them to other drainage 
channels. 
If any such old outlets exist, they would furnish almost a 
demonstration of the reality of this supposed glacial lake, 
*A "G. S. A." paper, read before Section E. of "A. A. A. S.," at 
the Buffalo meeting, August, 1896. 
