quartzite nodules. When found, these were broken into convenient blanks for transport, while the chips and rejected pieces were left behind where they serve to mark the site. In addition to these localized works, we find scattered everywhere in the great central reaches of the area, circles and lines of boulders, with an occasional effigy in outline. The small circles are assumed to mark tipi sites; but long lines of stones have been noted whose use is problematical, though in Montana the historic Indians claim them as markers for buffalo pounds. About the only other permanent evidences of man's work are the numerous pictographs pecked into the faces of rocks and ledges. Though not carefully studied, these seem to fall into two types, one of which is quite modern. Pottery is not found in the heart of the area, but stone vessels of original form are rather numerous. These are often crude, suggesting hollowed-out boulders, though some are dressed to the shape of an egg, while others are roughly pyramidal. All these data lead us to suspect that a more systematic survey of the true archæological center of the Plains will clearly define a distinct type of prehistoric culture.
7. The Pueblo Area. In the states of Arizona and New Mexico centers the richest archæological province north of old Mexico. For years ruthless relic hunters have overrun it, turning over burial grounds and knocking down ruined walls in their search for marketable plunder, without exhausting the supply. Also a number of distinguished archæologists have spent the active years of their lives surveying groups of these remains, but notwithstanding all this, whole regions are still unknown. Thus, though some progress has been made in the cultural analysis of the area, the greater part of the task remains unraveled.
If we consider first the general geography of the country, the mere topography seems to segregate the ruins into four large groups: those of the Rio Grande drainage, the San Juan, the Little Colorado, and the Gila. These four river valleys contain by far the greater part of the known sites. By using these gross distinctions as the points of departure, we can the more readily summarize the present state of the subject.
