The ruins in the Navaho Monument have ceremonial rooms allied on one side to the kivas of the San Juan region, and on the other to rooms in the Little Colorado ruins that may have been built for ceremonial use. The latter are constructed above ground, inclosed by other houses, and are rectangular in shape, with lateral doorways. Some of these rooms, as at Betatakin, contain each a fire screen and a fire-hole, as in a circular kiva, the ventilator being replaced by a lateral doorway. It is possible that when the Snake people inhabited their northern homes, before they came to Walpi, their ceremonial rooms were not built, as at present, partly underground, and placed at a distance from the secular houses. The ceremonial rooms of this clan and of immediate relatives when living at Tokónabi or in the Navaho Monument region may have resembled those of the Black Falls cluster of ruins.[40] Their subterranean position and separation from other rooms may be regarded as modifications due to foreign influences after the clan arrived at Walpi.[41] [Illustration: BUREAU OF AMERICAN ETHNOLOGY BULLETIN 50 PLATE 15 _a._ FOOD BOWL Cat. No. 257781. Diameter, 4½ inches. _b._ CLAY DISK WITH PERFORATED BORDER Cat. No. 258330. Diameter, 5¼ inches. _c._ DIPPER Cat. No. 257779. Height, 4½ inches. _d._ FOOD-BOWL WITH HANDLE Cat. No. 257780. Diameter, 6 inches. POTTERY FROM NAVAHO NATIONAL MONUMENT] The sunken or subterranean situation of the ceremonial assembly room, or kiva, of the Pueblo region is an architectural survival of a people whose secular and ceremonial rooms were subterranean. This feature may not be autochthonous in this area, or limited to it geographically, having probably been derived from people of kindred culture of the West coast, as pointed out by Mr. Ernest Sarfert’s argument on this point, which would seem to be conclusive if subterranean kivas could be found in the Gila and Little Colorado regions.[42] The forms of pueblo kivas, circular or rectangular, are not derived one from the other, but suggest different geographical origins. The circular form, confined to the eastern Pueblo area, bears evidence of having been derived from the culture of a people inhabiting a forested region; while the rectangular form strongly suggests a people with a treeless habitat. Both circular and rectangular subterranean assembly rooms existed in aboriginal California in historic and prehistoric times. The archaic or prehistoric culture of the Pueblo region is closely related to that of the West coast in other particulars also, that do not concern the subject of this article.