p. 1

1847

On the existence of certain Lacustrine
Deposits, in the vicinity of the Great Lakes,
usually confounded with the "drift:" -
By I. A Lapham.

Of all the subjects investigated by the
geologist, none are more interesting or have
attracted more attention within the last
few years, than those relating to the diluvial,
or drift and boulder formation; and although
much has been done to elucidate this obscure
point in the history of creation, and a
vast amount of facts and observations have
been collected and recorded, we are yet without
a satisfactory theory to account for the origin
of this extensive formation , that will explain
all the facts. One reason of this may
be that no one theory can be found sufficient;
the subject must be divided - and each portion
may admit of a different explanation.

These is no doubt that much of what
usually passes for drift in the region of the
Great Lakes, must be separated from it, and
attributed to a lacustrine origin, of more recent date. These deposits
consist of nearly uniform layers of fine clay
resting upon ^irregular beds of the sand, gravel, boulders and hard=pan of
^constitutng [constituting] the true drift. without [conforming?] The layers are
usually about from a quarter of an inch ^to three or four inches in thickness
and lie in nearly a horizontal position, not
conforming with the irregular layers of drift.
They ^beds sometimes attain the thickness of fifteen or
twenty feet. It is evident that these layers
were deposited when the water was calmr [calmer];
not [illegible]