Putnam.] 30 [February 7, 
From the northeastern corner of this wide wall the line continues 
northwesterly about 350 feet along the western ravine to a point 
where there is a spring, and the ravine makes an imdenture of 
nearly 100 feet to the southwest. The mouth of the indenture 
is about 75 feet in width, and the work is here strengthened by 
a double embankment (#, Ff’). The natural line of the work fol- 
lows this indenture and then continues in about the same northerly 
course along the banks of the ravine, to the narrow portion of the 
plateau about 550 ft. to the starting point. 
There is thus a continued line, in part natural and in part artifi- 
cial, which, if measured in all its little ins and outs, would not be far 
from 2450 ft. 
Besides the spring mentioned as in the indenture of the eastern 
ravine, there is another spring in the same ravine about 175 ft. to the 
north of the first, and a third in the southwestern ravine about 125 
ft. to the west of the southwestern corner of the work. 
Looking at all the natural advantages offered by this location it 1s — 
the one spot of the region, for several miles along the river, that 
would be selected to-day for the erection of a fortification in the vi- 
cinity, with the addition of the possession of a small eminence to the 
north, which in these days of artillery would command this fort. 
Having this view in mind a careful examination was made of the em- 
inence mentioned, to see if there had ever been an opposing or pro- 
tective work there, but not the slightest indication of earth work 
fortification or of mounds of habitation was discovered, though 
some five or six miles up the river on the Illinois side, at Hutsonville, 
a large group of some fifty-nine mounds of habitation were investi- 
gated. 
he interior of this fortification contains much of interest, and its 
history may yet be in part made out by a more extended examina- 
tion than it was possible to make during the few days given to its ex- 
ploration. 
On crossing the outer wall a few low mounds are at once noticed, 
and all arourd are seen large circular depressions. At the southern 
portion of the fort these depressions, of which there are forty-five in 
all, are most numerous, thirty-seven of them being located south of a 
line drawn from E, on the northern side of the indenture of the east- 
ern ravine, to the projecting extreme western point of the fort at H. 
These depressions vary in width from ten to twenty-five or thirty 
feet and are irregularly arranged, as shown by the accompanying en- 
