296. KANSAS CITY REVIEW OF SCIENCE. 
In this exploration the professors received valuable assistance from Mr. War- 
ren Upham, now Prof. Winchell's assistant at the Minnesota State University. 
Prof. Chamberlin is still prosecuting this search under the United States Govern- 
ment, and is recognized as one of the most thorough and erudite geologists con- 
nected with the government survey. Prof. Chamberlin and Mr. Upham have 
read papers in the geological section on this subject, which papers have already 
been reported. A valuable addition to the literature was a paper read Friday,. 
August 17th. It was written by Prof. I. C. White, and considered the surface 
deposits along the Monongahela River and other West Virginia tributaries of 
the Ohio on the hypothesis of a glacial dam across the Ohio valley near Cincin- 
nati. The following is the paper in full :] 
In a paper read before the Boston Society of Natural History, March 7, 
1883, Rev. G. F. Wright has shown that the southern rim of the great northern 
ice sheet crossed the Ohio River near the site of New Richmond, a few miles 
above Cincinnati. Mr. Wright believes that one effect of this invasion of the 
Ohio valley by the glacial ice, was to form an immense dam of ice and morainic 
debris, 500 or 600 feet high, which effectually closed the old channelway, and 
set back the water of the Ohio and its tributaries until rising to the level of the 
Licking River divide, it probably found an outlet through Kentucky, around 
the glacial dam. As this divide is 500 or 600 feet higher than the present bed of 
the Ohio at Cincinnati, Mr. Wright states that the site of Pittsburg would have 
been submerged to the depth of 300 feet; and adds: "It remains to be seen 
how much light this may shed upon the terraces which mark the Ohio and its 
tributaries in western Pennsylvania." 
Having resided for nearly a score of years in the valley of the Monongahela 
River, the writer is necessarily familiar with its terraces and surface deposits in 
general; and in reply to the above query of the eminent glaeialist, would answer 
that his admirable work throws a flood of light upon the Monongahela terraces,, 
and proffers for them, and the deposits along other tributaries of the Ohio, the 
only satisfactory explanation that has ever been advanced. 
Of course, if the Ohio River was ever so obstructed for any considerable 
period of time, it would follow, as a necessary result, that many of the tributary 
streams and the Ohio itself, above the limit of the dam, would have their old 
valleys silted up with vast heaps of trash — clay, sand, gravel, boulders, drifted 
logs, and other rubbish — carried down by the streams from the regions not- 
sheeted with ice, and dumped into the great inland lake-stream which extended 
from Cincinnati far up toward the sources of the Monongahela. 
That the valley of the latter stream has been refilled with trash during some 
period of its history to a height of 250 or 300 feet above its present bed, the 
evidence is most conclusive, for the remnants of this deposit still cover the sur- 
face to a great depth in long lines of terraces extending from Pittsburg, Pa., 
southward along the river to Fairmont, W. Va., a distance of 130 miles, and 
very probably much further, as I have never examined the river valley above the 
latter town. 
