164 PUEBLO ARCHITECTURE. 
These oceur on the east side of Mashongnavi. They project 6 or 8 
inches above the ground, and have a depth of from 18 to 24 inches, 
The débris scattered about the pits indicates the manner in which they 
are covered with slabs of stone and sealed with mud when in use. In 
all the oven devices of the pueblos the interior is first thoroughly heated 
by a long continued fire within the structure. When the temperature 
is sufficiently high the ashes and dirt are cleaned out, the articles to 
be cooked inserted, and the orifices sealed. The food is often left in 
these heated receptacles for 12 hours or more, and on removal it is gen- 
erally found to be very nicely cooked. Each of the pi-gumimi ovens 
illustrated above is provided with a tube-like orifice 3 or 4 inches in 
diameter, descending obliquely from the ground level into the cavity. 
Through this opening the fire is arranged and kept in order, and in 
this respect it seems to be the counterpart of the smaller hole of the 
Zuni dome-shaped ovens. When the principal opening, by which the 
vessel containing the pi-gummi or other articles is introduced, has been 
covered with a slab of stone and sealed with mud, the effect is similar 
to that of the dome-shaped oven when the ground-opening or doorway 
is hermetically closed. 
No example of the dome-shaped oven of pre-Columbian origin has 
been found among the pueblo ruins, although its prototype probably 
existed in ancient times, possibly in the form of a kiln for baking a fine 
quality of pottery formerly manufactured. However, the cooking pit 
alone, developed to the point of the pi-gummi oven of Tusayan, may 
have been the stem upon which the foreign idea was engrafted.  In- 
stances of the complete adoption by these conservative people of a 
wholly foreign idea or feature of construction are not likely to be found, 
as improvements are almost universally confined to the mere modifica- 
tion of existing devices. In the few instances in which more radical 
changes are attempted the resulting forms bear evidence of the fact. 
Fig. 54. Diagram showing foundation stones of a Zuili oven. 
In Cibola the construction of a dome-shaped oven is begun by laying 
out roughly a circle of flat stones as a foundation. Upon these the 
