A78 ARCHEOLOGICAL INVESTIGATIONS—II [BPH ANN. 44 
These exist to some extent in the south wall, disappearing within a 
few feet. Neither is there shown an irregular streak, broken in 
places, of reddish or brownish clay, nowhere more than an inch 
thick, which lies between the blue clay and the loess. It belongs 
entirely to the latter formation; in some places it is divided into 
two or more thinner bands, enclosing loess material and soon coming 
together again. 
Among those who have made a study of the earth which lies next 
above the clay there is some lack of agreement as to its origin. It 
is principally composed of the fine-grained, yellow, silt-like mixture 
of silt, sand, and clay, so firmly compacted that it m:¢ht almost be 
called microscopic concrete, which forms the bluffs along this part 
of the Missouri River. Whether it be true loess or not, it is so called 
in this paper for the reason that the term conveys a definite idea of 
its appearance. 
A ventilating shaft at the end of the tunnel showed that the 
loess measured 28 feet in thickness from the rock floor to the surface 
of the ground above: it was the same in character from top to 
bottom. It was equally uniform in all parts of the extension, A, 
to such height as it could be conveniently reached with picks—an 
elevation of about 8 feet above the floor. Lines, apparently of 
lamination or deposition, were visible in several places at different 
levels, but invariably ran out within a few feet and may have been 
only in the nature of pressure-joints. 
Snail shells were numerous, occurring one in a place in every part 
of the loess excavated; with very few exceptions they seemed to be 
of one species. Fragments of charcoal, perhaps 50 in all, varying 
from small specks to pieces more than 2 inches across, were also 
discovered here and there throughout the loess. In one fragment 
the grain was sufficiently preserved to show that it was burned from 
oak; another was willow or cottonwood; no others could be deter- 
mined with certainty. A dozen or more fragments of limestone were 
scattered at various levels from near the bottom of the loess to the 
roof of the tunnel, some of them 2 or 3 feet from any other piece of 
stone. The largest observed weighed about 3 ounces. None of them 
appeared waterworn; in fact, some of the angles were as sharp-cut as 
if freshly fractured. They could not have been carried in by winds; 
while from their small size and infrequency it is quite improbable 
that they worked down from rock strata in the vicinity. At present, 
the most reasonable explanation of their presence seems to be that 
they dropped from ice or the roots of trees, floating over the place 
where they lay. 
At one point, within a space a few inches in diameter, was a hand- 
ful of calcareous globular objects closely resembling the seeds of a 
hackberry, probably concretionary in their nature. 
