Mesa Verde National Park, Colorado 1

(9/18 and 9/19)

Mesa Verde is a high tableland (7 to 8 thousand feet) incised by deep canyons. The canyon rimrock is a thick sandstone formation (the Cliff House Sandstone) lying above shales (the Menefee formation). Because the shale is impermeable to water, springs emerge from the cliff face at the base of the sandstone. The water undermines the sandstone cliff face, causing alcoves to form.

Much of the mesa is covered with an old-growth (400 years +) Juniper-Pinyon Pine woodland. This greenery gives the mesa its name.

Human habitation on the mesa goes back to about 550 A.D. Once called Anasazi, the inhabitants are now referred to as Ancestral Puebloans, and they continued to inhabit Mesa Verde until the late 1200s, when they left for unknown reasons. For most of this period, they lived on top of the mesa. At first, they lived in pithouses, which had the living area sunk a few feet into the ground, with walls and ceilings formed of timbers covered with adobe.

Over time, they advanced to above-ground houses with stone walls and many rooms.

But they continued to include pit rooms as part of their housing complexes. These evolved to have circular stone walls and a sturdy roof with an entry hole. These pit rooms are called kivas and are believed to have had a ceremonial function.