1876.) Traces of an American Autochthon. 331 
isin every way applicable to the rude implements here consid- 
ered to be the production of an older people than the Indians. 
Again, on examination of a large series of these relics, consid- 
ered with reference to the circumstances under which they were 
gathered, it is found that the mineral of which they are almost 
exclusively made is not really a soft stone, easily worked ; nor on 
the other hand as dense as jasper or quartz. A freshly fractured 
surface will readily scratch glass. Their surfaces are, however, 
quite soft, from long exposure since their detachment from the 
parent rock. In fragments of a rock buried in ordinary soil, and 
not exposed to unusual chemical action, any decomposition, if it 
took place at all, must have been very gradual; indeed, inconceiv- 
al 
(Fie.21.) “ TURTLE-BACK” CELT. 
ably slow; and it seems more probable that these implements 
Were long exposed to the weather on or near the surface of the 
ground, before the slowly increasing deposit of soil or stratum of 
sand or gravel, as the case may be, concealed them from view. 
This “weathering ” of the surface of rude implements varies con- 
siderably in depth, but is not more noticeable on any one pattern 
of the few forms common to these older relics. It occurs on all, 
and the variation, ranging from „y to +}s of an inch, indicates, I 
lieve, a greater antiquity of the more deeply corroded speci- 
mens. A peculiarity which also tends to separate these rude 
2m from the more common or true Indian relics is the preva- 
n 
Ce of certain forms of a marked character, which do not occur 
