Mary’s Cave, also known as Shelter Rock, is a nice little rock shelter carved out of a volcanic rock formation in the Mojave National Preserve. There is a small tinaja (a depression in the bedrock made by water) next to the shelter in the canyon which would of held water for an extended period of time after a rain. That and the shelter itself would have allowed the Indians to live in this arid place for a little while longer. This is mostly Chemehuevi and Mohave territory, but it is likely that the Desert Archaic culture used this area before them.
Researchers also note that it is possible this is a solar observation site. The summer solstice and spring and autumn equinoxes line up well with notches on the distant eastern horizon at sunrise. Sunlight entering this cave would have marked the starting of spring and a renewal of the land.