128 CASA GRANDE, ARIZONA [BTH: ANN. 28 
than broad; a and } show no sign of coneavity; and e is barely more 
than a flat stone. 
From the simple mortars last mentioned we pass to those more 
elaborately made, shown in plate 60. Specimen 6 is rectangular, with 
a thin border surrounding a shallow smooth concavity. The rim of 
the depression is raised at each end, differing in this respect from f, 
which is practically a metate. Specimen e is much longer than 
broad, the depression resembling a groove rather than a concavity, 
while figure d in addition to a raised rim has bars across the rim, 
approxumating in form a tablet (p. 125). Specimen ¢ resembles a 
miniature metate but may be a concretion of symmetrical shape. 
Fic. 29. Tool for rubbing or grinding pigment. 
The two mortars shown in plate 65 are typical, the one (a) oval, the 
other (b) circular in shape. They were doubtless used as at present 
among the Pima in bruising mesquite beans and in crushing seeds. 
The cavity was either worn out by constant use or it may have 
been worked out with pecking stones. The lava of which these mor- 
tars were made, both a soft porous kind and a hard compact variety, 
is found in the mountains near Casa Grande. 
Although there are in the collection no wooden pestles to use with 
these mortars, the native ironwood was well adapted for the purpose 
and no doubt was so employed. 
