To the northwest of Aztec, between the La Plata Mountains and the Sleeping Ute, in and around the area dominated by the large tableland of Mesa Verde, a second regional culture center developed. These Indians lived along the main watercourses of the area—the McElmo and Montezuma—or dry-farmed the surrounding mesas. It was toward the end of this period that the Indians living in the Mesa Verde itself built their large imposing cliff dwellings. [Illustration: Mesa Verde-style masonry wall.] By the end of the preceding Developmental Pueblo Period the communities in the San Juan area began to be more centralized and to be built according to preconceived plans. Such planning denotes a form of community control, or at least some kind of control over a fair-sized labor force. Today, community projects are frequently carried out in the pueblos by the majority of the people under the direction of their caciques, or leaders, after careful discussions and proper religious observances by the elders of the group. A similar form of self-government must have existed in the prehistoric pueblos. It was probably based on a time-honored tradition given sanction by religious beliefs which extended back as far as the late Basketmaker period where there were beginnings of large community kivas and centralized religious group activities. With large groups of people living together, greater cooperation was mandatory, and through such cooperation the necessary tasks were accomplished more quickly. Thus there was greater leisure for many people which could be devoted to the more interesting arts and crafts. Sometimes societies limit this greater freedom and leisure to a ruling class, but such does not seem to have been the case among the Pueblos. There are some indications, however, that especially in this period there may have been developing the concept of a priestly hierarchy that also exercised civil controls. The Great Pueblo Period was a period of continued specialization, not only in architecture but also in ceramics and in the minor arts and crafts. North of the San Juan, most of the pottery seems to have been decorated with a carbon paint, that is, a paint made from vegetal dye. South of the San Juan, in the Chaco area, they generally seem to have used mineral paints. The pottery designs of this period were often hachured patterns, with the thin filling lines surrounded by heavier boundary lines. Band designs of steps, frets, and triangles were also used. Bowls, pitchers, ollas, and ladles were the common shapes; and some cylindrical vessels and effigy pots are known. An equally popular ware, which was not painted, was the cooking, or “corrugated” ware mentioned earlier. In this period the coils of the vessel wall were still sometimes pressed together to form decorative designs, or sometimes were smoothed over so that an almost-plain vessel resulted. [Illustration: Chaco-style pottery pitcher. Diameter at mouth, 2½″; Maximum diameter, 4″; Height, 6¼″.]