l80 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I47 



The distinctive Chaco-type ventilating system is a 3-part combina- 

 tion : an air vent near the fireplace, an under-floor duct, and an ex- 

 ternal shaft with air intake. Fresh air drawn down the shaft and 

 through the duct escaped at the vent and rose on fireplace heat and 

 out at the roof opening. Because the vent lay at floor level a 

 deflector was seldom required to screen the fireplace flame from in- 

 rushing air. Indeed, we have record of only seven such deflectors 

 (H, L, M, Q, T, 2-B and 2-E), none more than a few inches high and 

 one of them in a non-Chaco kiva. Fireplaces, as we observed them, 

 are usually circular but may be either masonry-lined or slab-lined. 



Of all our Chaco-type kivas only L was as its builders left it, 

 with ceiling intact or nearly so. We dismantled this ceiling piece by 

 piece, counted 195 individual pine logs in the principal cribwork, 135 

 shorter pieces completing and leveling the fourteenth or uppermost 

 layer (pi. 56, upper), and guessed that perhaps 20 more had been 

 lost with collapse of the middle portion, a total of 350. If this total is 

 typical, and there is no reason to believe otherwise, one can under- 

 stand why the sparse Chaco forests ultimately were exhausted. 



The Kiva L cribwork included 14 layers of clean pine logs or 

 sections of logs that rose domelike from six basal pilasters 9^ inches 

 high. The four lowermost layers consisted of six logs each, paired 

 and extending between alternate pairs of pilasters, but the number per 

 layer gradually increased thereafter, as follows : 



Sequence of roofing poles, Kiva L 



Pilasters* 1. 2. 3. 4. 5. 6. 1 



Layer 1 2 —2— 2 



5 3 3 3 



6 i 3 4 



7 4 4 4 



8 —5 4 4 



10 5 6 5 



11 5 5— 5 



12 8 7 8 



13 10 9 8 



14 8 12 10 



♦ Numbered counterclockwise from the south recess. 



Each layer above the three lowest was braced both ways by a 

 longer member (pi. 56, lower). 



