the reliability of scoring for teosinte introgression accord- 
ing to the degree of induration by showing that the more 
indurated archaeological cobs are like modern maize- 
teosinte derivatives in having a higher specific gravity 
which is also positively correlated, in modern maize, to 
number of teosinte chromosomes. 
According to this system, induration is subjectively 
estimated with an arbitrary key of five grades. At grade-1 
the glumes and rachis are non-indurated and somewhat 
flexible. At grade-5 the glumes and rachis are not only 
highly indurated, but the glumes are curved upwards 
and at least some pistillate spikelets are borne singly, 
features which are common in maize-teosinte hybrids, 
but absent in typical maize. 
By applying this method to estimate teosinte intro- 
gression in the present stratified material, we may now 
determine the evolutionary effects of such introgression 
upon the maize from this site. 
Description of the Site 
The archaeological maize upon which this study is 
based was excavated from Cebollita Cave in the Cebol- 
leta Mesa‘ area in Valencia County, New Mexico, about 
twenty miles south of the town of Grants. The area is 
bounded on the west by the McCarthys’ Lava Flow and 
on the east by the western slope of Cebolleta Mesa. It is 
in the Upper Sonoran climatic zone at an elevation of 
about 7000 feet. The terrain consists of broad valley 
floors and sheer sandstone cliffs. The cave is located in 
a vertical sandstone cliff in the Zuni sandstone member. 
It faces south and opens out on a broad valley, which, 
' According to the principal maps of the area, the name of the mesa 
is spelled Cebolleta while the name of the cave which contained the 
archaeological maize is spelled Cebollita. The latter spelling comes 
from the Spanish word meaning “‘little onion.”’ 
[ 164. ] 
