with those of modern Chapalote from the Mexican states 
of Sonora and Sinaloa and with those of certain early 
Basket Maker ears (about 800 A.D.) obtained from the 
studies of Hurst and Anderson (1949) on maize from 
Cottonwood Cave, Colorado, reveals that the ears from 
Cebollita Cave are slightly smaller (Table 1). The date 
of the Cebollita maize (about 1050 A.D.) seems to ex- 
clude it as a more primitive or inherently smaller type 
of Chapalote. Rather, reduction may be a depauperate 
condition resulting from poor growing conditions. The 
latter suggestion is supported by the fact that the best 
Level 5 ears compare favorably to those of modern Chap- 
alote and Cottonwood Cave maize. 
The termination of Level 5 was marked by a fire which 
either carbonized or charred all of the original Chapalote 
cobs and caused a large rock fall from the ceiling, as well 
as a temporary abandonment of the cave. 
Level 4 Maize 
Upon reoccupation of the cave, as designated by Level 
4, 859% of the cobs changed abruptly to the Tripsacoid 
type of maize which was becoming widespread through- 
out southwestern United States during this period (1000— 
1200 A.D.). Three percent of these were almost exact 
counterparts of modern Fy; hybrids or hybrid segregates 
from experimental crosses between maize and teosinte in 
being two-ranked for at least part of their length, and in 
having highly indurated, upward-curved glumes (Plate 
XXII, cobs C, D). Such highly Tripsacoid cobs were 
scored as grade-5 according to our system of estimating 
the degree of teosinte introgression with an arbitrary key 
of five grades. On the average, the Level 4 specimens 
were the most 'Tripsacoid from the entire site, having an 
average introgression grade of 2.6. 
At the other extreme, fifteen percent of the Level 4 
[ 169 ] 
