tween the Mississippi and Ohio, extending to their junction. This
area constitutes the grand prairie section of lower Illinois. The Big
Bone Lick of the Ohio, the original seat of the discovery of the bones
of the megalonyx and mastodon, announced by Mr. Jefferson to the
philosophers of Europe, connects itself with this element of
continental disturbance. Its western limits are cut through by the
Mississippi, which washes precipitous cliffs of rock, between a
promontory or natural pyramid of limestone, standing in its bed called
Grand Tower, and the city of St. Louis, extending even to a point
opposite the junction of the Missouri. Directly opposite these
secondary cliffs, on the Illinois shore, extends transversely for one
hundred miles, the noted alluvial tract called the American bottom.
This tract discloses, at great depths, buried trunks of trees,
fresh-water shells, animal bones and various wrecks of pre-existing
orders of the animal and vegetable creation. On the banks of the Sabine
river, which flows into the Ohio, there was found, some few years ago,
in the progress of excavations made for salt water, coarse clay kettles
of from eight to ten gallons capacity, and fragments of earthenware,
imbedded at the depth of eighty feet. The limestone rocks of the
Missouri coast, above noticed, which form the western verge of this
antique lacustrine sea, have produced some curious organic foot-tracks
of animals and other remains; and the faces of these cliffs exhibit
deep and well marked water lines, as if they had been acted on by a
vast body of water, standing for long and fixed periods, at a high
level, and subject to be acted on by winds and tempests. Indeed, it
requires but little examination of the various phenomena, offered at
this central point of the Mississippi valley, to suppose that the
southern boundary of this ancient oceanic-lake, ran in the direction of
the Grand Tower and Cave in rock groups, and that an arm of the sea or
gulf of Mexico, must have extended to the indicated foot of this
ancient lacustrine barrier. At this point, there appear evidences also
of the existence of mighty ancient cataracts. The topic is one which
has impressed me as being well entitled to investigation, and is
hastily introduced here among the branches of inquiry bearing on my
subject. But it cannot be dwelt upon, although it is connected with an
interesting class of kindred phenomena, in other parts of the west.

I have already