250 Obsidian in the Yellowstone National Park. [April, 
< tion by specialists in petrography will doubtless develop many 
new and interesting features, as no equally rich deposit of similar 
rocks has heretofore been brought to their notice in this country. 
Indian Implements.—It occurred to me, while making examina- 
tions at this point, that the various Indian tribes of the neighbor- 
ing valleys had probably visited this locality for the purpose of 
procuring material for arrow-points and other implements. A 
finer mine could hardly be imagined, for inexhaustible supplies of 
the choicest obsidian, in flakes and fragments of most convenient 
shapes, cover the surface of the country for miles around. 
Having climbed the promontory, I observed that. an old but 
quite distinct trail passed along the brink of the ledge and 
descended the broken cliffs to the valley above and below. In 
the vicinity of the trail the glistening flakes proved to be more 
plentiful than elsewhere, and were also apparently gathered into 
heaps. After a short search a leaf-shaped implement of very fine 
workmanship was found ; it is made of the black opaque obsidian, 
and is four inches in length, three inches in width and one-half an 
inch in thickness ; an outline of this implement is given in Fig. 
1. Having continued the search as long as the time at my com- 
mand would permit, I was amply rewarded in the possession of 
ten more or less perfect implements. Three are leaf-shaped and 
nearly the same in size as the first specimen found, but imperfect 
from having been broken. One is somewhat pyramidal in shape, 
as shown in Fig. 2; the bottom is flat, the flaked surfaces ex- 
tending from the base to the apex; it is two and a half inches 
in width and one and three-quarters in height, and is the only 
specimen in the collection that appears to have been in the least 
used ; the sharp edge at the base is considerably worn; Fig. 3 is 
a top view of the same. Another specimen is triangular in shape 
with sides about three inches long; another is rectangular and 
about three inches wide by four in length, and still another is a 
rude oval; nearly all of these implements are imperfect, as it 
broken or unfinished. If we are to suppose that the great quan- 
tities of minute flakes are the fragments left from the manufacture 
of implements we must conclude that extensive supplies have 
been obtained here, but by what tribes or at what period it will 
be quite impossible to determine. 
