194 THE CLIFF RUINS OF CANYON DE CHELLY (ETH. ANN, 16 
migrations from place to place, the statements being more or less 
obscured by mythologic details and accounts of magic or miraculous 
occurrences. When numbers of such movements are recorded, it is safe 
to infer that the conditions dictating the occupancy of sites were unsta- 
ble or even that the tribes were in a state of slow migration. When 
this inference is supported by other evidence, it becomes much stronger, 
and when the supporting evidence becomes more abundant, with no 
discordant elements, the statement may be accepted as proved until 
disproved. 
The evident inferiority of the modern pueblos to some of the old ruins 
has been urged as an argument against their connection. While degen- 
eration in culture is yet to be proved, degeneration of some particular 
art under adverse conditions, such as war, continued famine, or pesti- 
lence, is not an uncommon incident in history, and it can be shown that 
under the peculiar conditions which prevailed in the pueblo country 
such degeneration would naturally take place. One of the peculiari- 
ties of pueblo architecture is that its results were obtained always by 
the employment of the material immediately at hand. In the whole 
pueblo region no instance is known where the material (other than tim- 
ber) was transported to any distance; on the contrary, it was usually 
obtained within a few feet of the site where it was used. Hence, it 
comes about that difference in character of masonry is often only a 
difference in material. Starting with a tribe or seyeral tribes of plains 
Indians, who came into the pueblo country, we should probably see 
them at first building houses such as they were accustomed to build— 
round huts of skin or brush, perhaps partly covered with earth, such 
as were found all over middle and eastern United States. Supposing 
the tribe to have been not very warlike in character and subsisting 
principally by horticulture, these settlements would necessarily be con- 
fined to the vicinity of springs and to little valleys where the crops 
could be grown. The general character of the country is arid in the 
extreme, and only in favored spots is horticulture possible. In a very 
short time these people would be forced to the use of stone for build- 
ings, for the whole country is covered with tabular sandstone, often 
broken up into blocks and flakes ready for immediate use without any 
preparation whatever. Timber and brush could be procured only with 
difficulty, and often had to be carried great distances. 
It has been suggested that the rectangular form of rooms might have 
been developed from the circular form by the crowding together upon 
restricted sites of many circular chambers; but such a supposition 
seems unnecessary. A structure of masonry designed to be roofed 
would naturally be rectangular; in fact, the placing of a flat roof upon 
a circular chamber was a problem whose solution was beyond the 
ability of these people, as has already been shown. Along with this 
advance, or perhaps preceding it, the social organization of the tribe, 
or its division into clans and phratries, would manifest itself, and those 
who *‘belong together” would build together. This requirement was a 
very common one and was closely adhered to even a few years ago, 
