4 GEOLOGY OF OHIO. 
elephant, mastodon, and giant beaver are found in and above the Forest 
Bed, but nowhere yet below it. 
6th. Above the old soil which has been described we find a series of 
stratified deposits, sometimes of considerable thickness, evidently the 
product of a submergence by which a large land area was deeply buried 
beneath a mass of transported material. In southern Ohio these later 
Drift deposits consist of white, laminated brick-clay, yellow and blue 
clays, the latter containing bowlders, and sometimes heavy beds of gravel 
and sand. In the northern counties of Ohio the upper strata of the Drift, 
and the equivalents of those last mentioned, are laminated, usually some- 
what sandy clays, and locally beds of sand and gravel, which, from the 
fact that they have been washed down from the watershed, and have 
been transported by the draining streams, have been sometimes referred 
to as the Delta sand deposit. In western Ohio, Indiana, Illinois, etc., the 
uppermost stratum of the Drift is called the Loess or Bluffformation. All 
the deposits enumerated in this note are the products of the last sub- 
mergence, and I have termed them the Lacustrine Drift. They will be 
described in detail in another place. 
7th. Upon the clays, sands, gravels, etc., last mentioned are scattered 
bowlders and blocks of all sizes of granite, greenstone, silicious and 
mica slates, etc., etc., generally traceable to some locality in the Eozoic 
area north of the lakes. Among these have been found many masses of 
native copper, which were plainly derived from the copper district of 
Lake Superior. These bowlders are found on nearly all the drift-covered 
area of the State; being scattered over the summit of the watershed, 
and reaching south nearly or quite to the Ohio. The margin of the 
bowlder area seems to mark the outline of the great ice-sheet at the 
period of its greatest development, but most of the bowlders strewed over 
this area appear to have been deposited by another agency, at a much 
later date. The greater part of them lie on or near the surface, and in 
many instances they rest on beds of purely laminated clay, and hence 
could never have reached their present positions through the agency 
of glaciers or powerful currents of water. They must, therefore, have 
been floated to their present resting places. The evidence is conclusive 
that they were transported by icebergs, and hence I have called them 
the Iceberg Drift. : 
8th. The highlands of Ohio, as well as in Michigan, New York, Wis- 
consin, etc., are locally occupied by hills, ridges, and banks of well 
rounded gravel and sand, with some bowlders which correspond closely 
with the “‘ Kames” and ‘“ Eskers” of the Old-World Drift. These peculiar 
accumulations of drifted material were evidently produced by special and 
