• Overlooking Chetro Ketl

    Chaco Culture

    National Historical Park New Mexico

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  • Kin Bineola and Kin Ya' a Great Houses CLOSED

    There is no public access.

  • Reservations required to attend equinox sunrise program

    To attend the equinox sunrise program on Monday, September 22 call the visitor center at 505-786-7014. Program will be limited to 100 participants.

Lewis Shale

Lewis Shale
Lewis Shale
NPS Photo by Phil Varela
Petrified Tree Stump in Lewis Shale

Petrified Tree Stump in Lewis Shale

NPS Photo by Tom Lyttle

The Lewis Shale is an olive-gray marine shale thinly interbedded with claystone, siltstone and sandstone as well as scattered beds of limestone. It overlies the Cliff House Sandstone and is exposed only near the northern boundary of the park. This unit was deposited at water depths greater than the Cliff House Sandstone and represents the last significant transgression of the Western Interior Seaway into northwestern New Mexico. Few fossils have been found in the Lewis Shale unit within the park.

Did You Know?

Photo of Chaco Wash

The climate of Chaco Canyon 1,000 years ago was very similar to the climate in the park today, with annual precipitation of only eight to nine inches. The Puebloans constructed water control features like dams, canals, and headgates for farming in such a dry environment.