Often overlooked, they're among the most abundant signs of our region's ancient human past. To encounter one in a remote corner of West Texas – the caprock canyons, the Devils River, the Big Bend desert – is to be reminded how thoroughly this land has been lived in.

“Ground-stone bedrock features” are holes in stone that prehistoric peoples used to prepare food. From shallow depressions in boulders to deep mortars in limestone shelves, there are tens of thousands in West Texas. 

Archeologist Amanda Castañeda analyzed more than 800 bedrock features in the Lower Pecos canyonlands. Her work sheds new light on a technology at the heart of ancient life.

Their use was global. Fr...