480 General Notes. [May, 
Amongst the relics of the past turned up by the modern 
plough the aboriginal stone ax is the most conspicuous and 
abundant. The numerous specimens show that but one general 
form and type prevailed, and that the material in all was nearly 
the same—a compact, firm, dark-green dolerite. Availing doubt- 
less of the river-worn boulders nearest to the desired form, the 
ancients shaped them by rubbing or grinding into axes of superior 
form and finish, capable of doing good service in cutting and 
hewing the soft cottonwood trees of the lowlands and even the 
a mezquite of the first terrace where their homes were 
uilt 
The form of the ax is best described by the accompanying 
figures, in side view and top view. The groove or channel for 
the org or thong of rawhide for the handle is generally deep 
and left somewhat rough in surface, while the rest of the ax is 
ground smooth and is polished. In some specimens, however, 
the groove is also smooth and polished as if by long wear. - 
groove extends across the top of the ax and down the two sides, 
but not across the bottom, or under edge, which is left straight 
and is ground smooth, apparently for the reception of a key 0f 
wedge to tighten the clasp of the thong on the stone, In many 
specimens particularly in the heavy hammers or sledges, also 
found here, the borders of the groove are raised in a ridge @ 
quarter of an inch or more above the general surface, thus giving 
a broader and firmer bearing for the thong while the blade and 
ead of the ax are made smaller and thinner. 
_ The thickness of the axes varies considerably, as also ee 
ee EN due in Pe to wear by long use and repeated grinding: 
