the side of the bluffs. At this place there are highlands on both sides
of the river which become more level at some distance back, and
contain but few streams of water. On the southern bank, during this day,
the grounds have not been so elevated. Captain Clarke crossed the river
to examine the remains of the fortification we had just passed.

[Illustration: Fortification]

This interesting object is on the south side of the Missouri, opposite
the upper extremity of Bonhomme island, and in a low level plain, the
hills being three miles from the river. It begins by a wall composed of
earth, rising immediately from the bank of the river and running in a
direct course S. 76°, W. ninety six yards; the base of this wall or
mound is seventy-five feet, and its height about eight. It then diverges
in a course S. 84° W. and continues at the same height and depth to the
distance of fifty-three yards, the angle being formed by a sloping
descent; at the junction of these two is an appearance of a hornwork of
the same height with the first angle: the same wall then pursues a
course N. 69° W. for three hundred yards: near its western extremity is
an opening or gateway at right angles to the wall, and projecting
inwards; this gateway is defended by two nearly semicircular walls
placed before it, lower than the large walls; and from the gateway there
seems to have been a covered way communicating with the interval between
these two walls: westward of the gate, the wall becomes much larger,
being about one hundred and five feet at its base, and twelve feet high:
at the end of this high ground the wall extends for fifty-six yards on a
course N. 32° W; it then turns N. 23° W. for seventy-three yards: these
two walls seems to have had a double or covered way; they are from ten
to fifteen feet eight inches in height, and from seventy-five to one
hundred and five feet in width at the base; the descent inwards being