Wliite Clays of the Ohio Region. — Leverett. 19 
cliana Survey Reports the tracts covered h\ these clays are spoken 
of as "shxsh land," and in the Ohio Reports they are called the 
"white clay districts." It has also been known for some time 
that there are somewhat similar clay deposits in southern Ohio 
outside the glacial boundary. So far as I am aware these deposits 
outside the glacial boundary have never been correlated with the 
white claj's that cover the southern portion of the glaciated dis- 
trict, nor has a common origin l:)een ascribed to them. On the 
contrary, they have l)een attributed to quite distinct agencies and 
conditions in the one district from those which have been assigned 
in the other. The clays outside the glacial boundary have been 
quite generally attributed to a submergence caused by the h3'po- 
thetical Cincinnati ice-dam, while those within the glacial bound- 
ar}', being evidently incapaljle of explanation on this hypothesis, 
have been attributed to organic agencies such as plants, earth- 
worms, ants, beetles, etc. .which bring fine material to the surface.* 
It is the aim of this paper to show that these deposits are syn- 
chronous, that they have a common origin, that that origin was 
independent both of ice-dams and of organic agencies, and, fur- 
thermore, that they furnish important evidence concerning the 
sequence of events in this region during the glacial period. 
In the summer and autumn of 1889, I made an examination of 
the portion of the upper Ohi<j region in the vicinity of the sup- 
posed Cincinnati ice-dam, extending my observations up the river 
as far as the point where the glacial Ijoundary bears away to the 
northeast. Careful comparison was made between the white clays, 
or silts, on Beech Flats and adjacent districts in Pike, Highland 
and Adams counties, Ohio, lying outside Wright's glacial boundary, 
*The greater part of the literature, relating to these clay?, and also that 
relating to the Cincinnati ice-dam, is comprised in the following refer- 
•ences i 
E. Orton, Geology of Ohio, Vol i, 1873, pp. 444 446. 
E. T. Cox (and associates), The Coimty Reports of the Indiana Survey 
pertaining to the southeastern counties of Indiana. 
G. F. Wright, Amer. Journ. Sci., July, 1883; Glacial Boundary in Ohio, 
1884, pp. 73-76, 81-86; Ice Age in North America, 1889, pp. 326-350; Bull. 
No. 58, U. S. Geol. Survey, 1890, pp. 83-104. 
I. C. White. Proc. A. A. A. S., 1883, pp. 213-213; Glacial Boundary in 
Ohio (Appendix) 1884, pp. 81-86; Amer. Jour. Sci., Vol. 34, 1887, pp. 374- 
381; Bull. Geol. Soc'y Amer., Vol. i, 1890, pp. 477-479. 
J. P. Lesley, Penn. Second Geol. Survey (Z), 1884, pp. ix to xr. 
E. W. Claypole, The Lake Age in Ohio, Trans. Edin. Geol. Soc'y, 1887. 
T. C. Chamberlin, Bull. No. 58, U. S. Geol. Survey, 1890, pp. 17-38; Bull. 
Geol. Soc'y Amer., 1890, Vol. i, pp. 472-475, 478-479. 
F. Leverett, Proc. Boston See. Nat. Hist., Vol. xxiv, 1890, pp. 455-459. 
