White Claijs of the Ohio Region. — Lecerett. 23 
morainic features, though there is a nearl}' continuous sheet of 
till. A large portion of this till sheet is covered by a white clay 
which we have correlated with the white clay of the Ohio region. 
It is similar to that deposit in structure and thickness, and over- 
lies an old land surface with soil and leached subsoil. It may 
prove to be connected with the Ohio clays by a practically con- 
tinuous sheet, the deposit having been traced across Indiana ex- 
cept in the driftless portion of the state which has not yet been 
examined. 
The north Iwundary of this deposit is determined by a moraine 
of which it is apparently a dependency.* Northward from this 
moraine are several later ones, which were also formed under con- 
ditions of low altitude and slack drainage, as is shown by silt 
aprons which fringe their outer border. These moraines appear 
to have been formed in relatively rapid succession, no soil having 
been found separating the silts in their aprons from the under- 
lying till. They are succceeded on the north by a series of 
moraines which were formed under conditions of high altitude 
and rapid drainage as is shown by gravel aprons and gravel terraces 
leading southward from them. 
Returning to the Ohio district we find that the present north 
boundary of the white clays of southeastern Indiana and south- 
western Ohio, is determined by a moraine, but evidently it is 
not the moraine with which the deposition was connected. That it 
belongs to a later period is shown by moraine headed terraces in 
neighboring valleys which contain gravel and sand, indicating 
clearly that the}' were formed under conditions of high altitude. 
How far the advance, marked by this moraine, extended beyond 
the one which produced the silts is not known. Two instances 
have been found where silts similar to the white clay occur l)e- 
neath the till of the later invasion at points a few miles north of 
the moraine referred to. At Grreensburg, Indiana, which lies 
perhaps five miles from the border of the white clay district, 
Pres. Chamberlin found good exposures of fossil-bearing silt or 
loess beneath the till of the later ice-invasion (See Third Annual 
Report of the U. S. Geol. Survey, p. 333). At Wilmingl<jn, 
Ohio, which is also situated a few miles north from the north ])order 
*A line connecting the following; cities will show approximately the 
distribution of this moraine: Litchfield, liillsboro, Pana, Shelby ville, 
MattooD, Charleston, Paris and Terra Haute, 
