Progress in knowledge of the more ancient stone cultures in North America has made increasingly apparent the existence of a gap in time between the fairly well-known, modern North American Indian and his Paleo-Indian predecessors. The extent of the break presents a problem to both archaeology and geology. Obviously, it is possible to approach the problem by leading from the earlier horizons toward the later, or in the reverse direction. The expansion and development of the “alluvial chronology” affords a basis for approach from the later horizons, as the last events in this chronology are effectively dated in the pottery cultures of the Southwest. The discovery by Mr. Joseph H. Toulouse, Jr., of the stone artifacts of a hunting people, who did not use pottery, in the heart of the Pueblo area appeared to offer such an opportunity. It seemed that it might afford a series of stages transitional backward from the known dates of the Puebloan stages toward the remote Paleo-Indians. The geologic results raise more problems than are solved, yet have some importance in extending knowledge along the fringes of the problem.