Cofi'exjKmfience. 215 
Jlchitioit of III! AttciniaU'<l Drift Jtonlrr to the Outer Mdrahie in Ohio. I 
am much surprised at a statement wliich Prof. Wright makes in the 
February Grolckiist concerning the relation of the oldest moraine 
which I have traced in Ohio to tlie attenuated border of the drift 
sheet, tiie statement being that my studies support his view that the 
fringe is but an appendage of the moraine. Tlie error contained in 
this statement is so great that I must ])eg leave to correct it by call- 
ing attention to the following facts: 
1st. The moraine in question lies back from fifteen to forty miles 
from the glacial boundarj' and the interval between the moraine and 
glacial boundary is in the main an elevated district covered with till 
and not with overwash material. Roth the width of the interval and 
the character of the drift material forbid our considering this sheet 
of drift a dependency of the moraine. 
2d. The course of the moraine in southwestern Ohio is not at all 
in harmony with that of the glacial boundary, there being a reentrant 
angle in the moraine opposite a southward protrusion of the boundary, 
and a ]irotrusion of the moraine opposite a re-entrant angle in the 
boundary, a lack of harmony which causes the distance between the 
moraine and the boundary to range from fifteen miles up to fully 
forty miles. (The distance between tlie glacial boundary and this 
moraine is found to be far greater upon tracing the moraine westward, 
being in Illinois at least 120 miles.) 
3d. The deposition of the outer sheet of drift is separated fronv 
that of the moraine by a time interval as great as has yet been found 
anywhere in the complex series of glacial deposits within the eastern 
lialf of the Mississippi basin. This time interval involves, (a) The 
development of a soih attended by oxidation, leaching, and erosion of 
the surface of the extra-morainic drift. (I)) A depression of the re- 
gion from a level a[)parently as great as the present (800 to 1,000 feet 
A. T.) down to a level vvitliin the reach of Hooded stages of tiie 
streams, there being upon tiie eroded and weathered surface of the 
uplands a silt dejiosit several feet in depth, locally known as white 
clay, which is to all ap])earance a water deposit, (c) A re-elevation 
to an altitude as great as the present accompanied by great erosion 
of the loess and associated silts along the principal drainage lines, 
after which deposits of coarse gravel we're made by the glacial floods 
which occurred at the time when the morainic line under discussion 
was occupied by the ice-sheet and which lead down the valleys at lev- 
els far below(300 to 400 feet) the level of the uplandsilts just mentioned. 
In other words there were between the time when the ice-sheet 
reached the glacial boundary and the time when the moraine under 
discussion was formed three distinct depositions separated from each 
other by long intervals marked by considerable orogra})liic movements 
as well as by soil accumulation, oxidation and erosion. In view of 
these facts I cannot support Prof. Wright in the statement that my 
studies bring corroiioriilivc ex idciicc of his view that the old drift 
sheet outside llic inoraine is hnl mh :ii)|)Pii(lage of it. 
