1) Natural cattle pen 2) Valley of New Mexico 
A box canyon is a small ravine or canyon with steep walls on three sides, allowing access and egress only through the mouth of the canyon. Box canyons were frequently used in the American West as convenient corrals, with their entrances fenced. They were also used as kill sites for wild game, which could be driven into the confined space and kille...
a canyon with steep side walls terminating headwards in a vertical cliff.