the occurrence of flint arrow heads and knives, in conjunction with
other evidences of human life, conclusive proof as to the antiquity of
the latter. Lyell informs us that some Oriental tribes still continue to
use the same stone implements as their ancestors, "after that mighty
empires, where the use of metals in the arts was well known, had
flourished for three thousand years in their neighborhood;" [Footnote:
Antiquity of Man, p. 377.] and the North American Indians now
manufacture weapons of stone, and even of glass, chipping them in the
latter case out of the bottoms of thick bottles, with great facility.
[Footnote: "One of the Indians seated himself near me, and made from a
fragment of quartz, with a simple piece of round bone, one end of which
was hemispherical, with a small crease in it (as if worn by a thread)
the sixteenth of an inch deep, an arrow head which was very sharp and
piercing, and such as they use on all their arrows. The skill and
rapidity with which it was made, without a blow, but by simply breaking
the sharp edges with the creased bone by the strength of his hands--for
the crease merely served to prevent the instrument from slipping,
affording no leverage--was remarkable."--Reports of Explorations and
Surveys for Pacific Railroad, vol. ii., 1855, Lieut. Beckwith'S Report,
p. 43. See also American Naturalist for May, 1870, and especially
Stevens, Flint Chips, London, 1870, pp. 77 et seq.

Mariette Bey lately saw an Egyptian barber shave the head of an Arab
with a flint razor.]

We may also be misled by our ignorance of the commercial relations
existing between savage tribes. Extremely rude nations, in spite of
their jealousies and their perpetual wars, sometimes contrive to
exchange the products of provinces very widely separated from each
other. The mounds of Ohio contain pearls, thought to be marine, which