On the Lansing Man — Williston. 345 
walls of the excavation, could be found any foreign pebbles 
or other material. Above the debris and partly intermin- 
gled with it, the walls are composed of silicious, calcareous, 
grayish yellowish loess, of river origin. Interspersed 
through it are occasional pebbles of water-worn limestone, 
and from the roof were obtained quantities of rounded 
flinty and calcareous pebbles, a quarter to a half inch in 
diameter, and clearly water-worn. Gasteropods of four or 
five species were obtained from the walls of the excavation, 
and from the edge of the roof, nearly seven feet from the 
floor, Mr. Long and I dug a complete cast of a Unio, 
showing clearly the markings of both valves. 
The surface of the ground immediately above the site 
of the bones slopes upward toward the east, that is, toward 
the river valley, for less than one hundred feet to the sum- 
mit of a small terrace, fifteen feet higher up, overlooking 
the river valley, and upon which Mr. Concannon's house is 
situated. It is certain — I use the word with scarcely any 
hesitation — that originally at least thirty-five feet of river 
loess had covered the skeleton. Since 1844 the highest 
water of the Missouri river was in 1881. At that time the 
water reached, according to Mr. Concannon who has lived 
at the place for thirty-five years, to within twelve or thir- 
teen feet of the horizon of the bones. The high-water mark 
then was twenty-five feet above the low-water mark, mak- 
ing altogther seventy-two or seventy-three feet as the eleva- 
tion of the loess terrace above the river, and fifty-seven or 
fifty-eight feet as that of the present surface over the bones. 
I am aware that some of the geologists, who have re- 
cently examined the tunnel, while admitting that the mate- 
rial in which the bones were found is of river deposition, 
believe that most of the material above them is of wind 
construction. I regret to say that I must differ decidedly 
from this opinion. Water-worn pebbles in quantities sev- 
eral inches in thickness and thirty or more feet in extent, 
according to Mr. Butts, and complete shells of clams, are 
not what we would expect to find in aeolian deposits ! 
Perhaps a foot above the horizon of the bones there 
is a very distinct stratum of darker, more argillaceous mate- 
rial, from half an inch to three inches in thickness, traceable 
