The basic element of the culture growth, maize agriculture, was derived from the south and was taken up, fifteen to twenty centuries before Christ, by a previously resident long-headed, nomadic or semi-nomadic people of a culture perhaps not unlike that of the present desert Shoshoneans of Nevada, who did not practise skull deformation, and made excellent coiled basketry, sandals and twined woven bags, and used the atlatl or throwing stick in lieu of the bow, but whose dwellings were of an unsub stantial character. This postulated stage has been termed Basket maker I., or Early Basket-maker.
The newly-acquired art of agriculture led to a more settled life and to the development of more permanent houses ; but as yet pottery-making was unknown. This stage, Basket-maker II., is exemplified by remains found especially in south-central and south eastern Utah and in north-eastern Arizona.
At a later date pottery was introduced or possibly independ ently invented ; houses of the pit type, "slab-houses" with pole and-brush roof, were perfected and became grouped into villages, and bow and arrow began to supplant the throwing-stick; but the long-headed people still persisted. This was Basket-maker III., or Late Basket-maker, remains of which are found throughout the San Juan drainage of Utah, Colorado. Arizona and New Mexico, and in parts of the Little Colorado watershed in Arizona.
At a still later period skull-deformation was initiated (some believe that a new broad-headed strain superseded the ancient long heads) ; cotton was introduced; dwellings emerged from the ground, rooms became rectangu lar and were grouped more closely; structural coils were left unobliterated on cooking vessels and thus corrugated pottery orig inated. This stage, Pueblo I., or Proto-Pueblo, is represented by sites throughout the San Juan drainage and in parts of the Rio Grande, Little Colorado and up per Gila valleys. Black-on-white and neck-coiled pottery is char acteristic of the period, and the kiva, or ceremonial chamber, had its beginning.
The development of culture was rapid. A period of wide geo graphical extension marked by small-village life ; corrugated pot tery, often of elaborate technique, extended over the whole sur face of cooking vessels. This culture stage was Pueblo II. There was perhaps a decrease in the extent of territory occu pied, and certainly a concentration of population in certain areas, together with greater architectural and ceramic achievement and strong regional specialization. This was Pueblo III., the Great Period.
Subsequently large areas were abandoned, there appears to have been a considerable shrinkage of population, and there was a defi nite cultural degeneration. Corrugated pottery gradually dis appeared. This period, Pueblo IV., or Proto-Historic, was brought to a close by the colonization of the south-west by the Spaniards at the beginning of the 17th century.
The Historic or Pueblo V. stage is the period commencing with the Spanish settlement and continuing to the present time.
Thus were gradually evolved, over long periods, thousands of small houses built of masonry, associated with the ruins of which is black-on-white pottery that evidently originated in the San Juan drainage, spread in almost every direction until the culture represented by it extended roughly from Great Salt Lake and southern Colorado almost to the Texas border and southern New Mexico, eastward to the limits of New Mexico, and westward to the California boundary. Then
concentration commenced, seem ingly by the result of hostile pres sure, resulting in large many storeyed community pueblos, such as Pueblo Bonito and others in the Chaco canon in New Mexico. Regardless of the sites, these pueblo clusters were built with a view of defense—on mesa-tops which were well-nigh impregnable, or in valleys convenient to tillage, where the character of the buildings, often terraced one above another with a well protected court and with outer walls having only a single opening, bespoke their defensive character. Many such villages were large enough to house a population of several hundred. To this day the Hopi villages and Acoma retain their mesa-top situations, and only within the last few decades have ground-floor openings been provided in place of ladders and hatchways. Some of the mesa top pueblos were further protected by low masonry walls at vulnerable points of the cliff.
In addition to the use of stone as building material in the mesa and valley pueblos and in the cliff-dwellings, a form of concrete was used in constructing certain massive buildings in the southern area, such as the well-known Casa Grande in Arizona (the prin cipal building of a large compound of circumvallated structures), the main walls of which, three to five feet thick, rise to a height of 20 to 25 feet, equivalent to two stories; but in 1699 it was four storeys high. The dimensions are 43 by 59 feet. Such edifices were erected by planting two rows of posts as far apart as the width of the walls was to be, wattling the posts with osiers, and tilling this form, pise-fashion, with mud made of the calcareous soil, which when dry became very hard. Moulded adobe bricks were not used in prehistoric times, but mud mixed with sage was rolled into the form of loaves and used for wall-building. "Wattle and-daub" was occasionally employed for unexposed walls. The kiva, or ceremonial chamber, usually circular and wholly or partly subterranean, was a common feature of ancient as of modern pueblos, and their large number compared with the rectangular domiciles in cliff-dwellings, notably those of the Mesa Verde in Colorado, recalls early Spanish reference to their occupancy in the pueblos by the male inhabitants in addition to their use for religious rites. Especially in southern Arizona, the inhabitants of the villages composed of many large community clusters built of concrete like Casa Grande, cultivated extensively by means of irrigation, their canals sometimes extending for many miles and their storage reservoirs being of great capacity.