AVERY CANYON. Avery Canyon is the bed of an intermittent stream through rugged Chihuahuan Desert terrain to the northeast of the Chisos Mountains in Big Bend National Park.^qv The head of the canyon, two miles southwest of the park headquarters at Panther Junction (at 29°20' N, 103°14 W), lies on alluvial fans against the high Chisos Mountains. Following a generally northeasterly course, the canyon then crosses Cretaceous clay and sandstone and becomes a deep defile with walls up to 250 feet high between Hannold Hill to the southeast and the Grapevine Hills to the northwest. At the end of a winding 16½-mile course the canyon empties into Tornillo Creek about one-quarter mile upstream from the U.S. Highway 385 bridge (at 29°25' N, 103°09' W). The area's biology is characteristic of the deep Chihuahuan Desert. For the most part, the land is sparsely vegetated; the most common plants include such shrubs as creosote bush and ocotillo and such semisucculents as lechuguilla and yuccas. There are also scattered grasses in the area, including gramas and fluffgrass. The desert scrub in turn shelters and supports the rich variety of animal and bird life typical of the Chihuahuan Desert. The name of the canyon derives from J. C. Avery, who was a rancher in this area of the low Big Bend country from 1901 to 1909.

BIBLIOGRAPHY: A. Michael Powell, "Vegetation of Trans-Pecos Texas," in New Mexico Geological Society Guidebook (Socorro, New Mexico: New Mexico Geological Society, 1980). David J. Schmidly, The Mammals of Trans-Pecos Texas (College Station: Texas A&M University Press, 1977).