Wherever they have studied early civilizations, scholars have been wont to consider that the nature of the country finally settled upon had no inconsiderable influence upon the forms of buildings there erected. Fewkes believes that “the cliffs in which are the ruins of the Navajo Monument favored the construction of cliff dwellings rather than of open pueblos.”[115] Caverns large and small, trees for beams and rafters, in short, all the conditions for cliff communities are there. It is incredible that the same conditions would not have had an effect as well upon the arts and crafts. The fantastic shapes into which the summits are eroded, and the great columnar forms of awesome size, cannot have failed to impress the primitive mind, developing conceptions of supernatural forms and agencies. Priority of origin between cliff dwellings and those on the level soil is an interesting question. The earliest villages were probably in river valleys or near small streams at the foothills of the many mesas. Later the Pueblo Indians removed to the more inaccessible sites on the summits of the mesas for protection from the nomad tribes who constantly harassed them by predatory raids upon their flocks and crops. The aboriginal Indians probably lived in detached houses, grouped more or less according to clans, or to the neighborhood of their planting fields. Gradually a more compact village or pueblo existence was found essential to protect the agricultural Indians from the nomad tribes. There are writers who believe, in accordance with the fond tradition of the native peoples, that the oldest villages on low ground were evolved from cave and cliff dwellings. Santa Clara, for example, in a flat region close to the Rio Grande, claims the cliffs of Puyé for its ancestral home as well as its temporary refuge in times of danger in later eras. On the other hand, Dr. Hewett[116] writes that he has indubitable proof that this claim is only one of many ruses employed by the Indians to secure their hold upon increased territory. No doubt in times of emergency Puyé was used by Santa Clara, but the “nation” never originated in these lofty cliff dwellings. In the case of Walpi the removal from the lower levels to the mesa top occurred within the historic period; Ácoma, we know, had been on its cliff summit long before the first white man saw it, nor has any record yet been found that does not connect it with the top of the great crag. At whatever period this change occurred from life on the arable ground-level to these easily defended cliffs, there must have resulted a fundamental change in the organization of existence. Permanent houses would be built only on the high stone table-lands, while the farms would be supplied with merely temporary dwellings. In some cases these farms would be actually overlooked, as at Walpi, by the mesa pueblo, or, as at Acomita, be a dozen miles distant from Ácoma.