Chaco Culture National Historical Park
Chaco Canyon, New Mexico

Scientists have determined that the Chaco culture used three different types of masonry over the 300 years of active construction. The three types are differentiated by the way they combined large flat stones, smaller "filler" stones, and adobe (clay mud, straw, and water) mortar. As they became more confident and advanced in their building techniques, the walls became more slender and elegant and less ponderous. Wood was at a premium in this desert environment, so it was used sparingly--as rough ceilings and over doors and windows.