Click on a masonry style for an enlarged color photo

The Chaco people were skilled masons. Working with stone tools, they erected vast communal buildings that still compel admiration. Their masonry techniques evolved over centuries. The earliest dwellings were built with simple walls one stone thick, with generous courses of mud mortar. The oldest walls in Pueblo Bonito used this type of masonry (1). When the Chacoans began to build higher and more extensively, they employed walls with thick inner cores of rubble and thin veneers of facing stone. These walls tapered as they rose to distribute the weight, evidence of the planning that went into the large-scale construction in Classic times (AD 1020-1120).

An early example of this wall (2) is characterized by large blocks of tabular sandstone chinked with smaller stones set in mortar.

About half the ground floor of Pueblo Bonito was built in masonry styles (3) and (4) (late 11th century). These styles were employed at roughly the same time. Though the patterns are attractive as they stand, there is evidence the Chacoans covered most of the stonework with plaster.

The last distinctive masonry style, called McElmo (5), appears in Kin Kletso, New Alto, Casa Chiquita, and in other early 1100s architecture. Kin Kletso's walls were built with a thin inner core of rubble and thick outer veneers of shaped sandstone resembling the masonry of the Mesa Verde region.