Grinding Hole

January 10, 2010

Grinding Hole

Photographer: Chris L. Grohusko
Summary Author: David Carmichael; Chris L. Grohusko

The photo above shows a mortar used by early North American cultures for grinding foodstuffs. It was taken from the base of Cornudas Peak, at the south face of the mountain, in southern New Mexico. These are what archeologists call bedrock or boulder mortars. Native Americans would gather plant materials from the desert environment and bring them to the mortars for processing – a mortar is used with a pestle. Wooden pestles are known from the region, but large cylindrical stone pestles were probably used with these. Very rarely are the pestles discovered in association with the mortars. In a location as well visited as the Cornudas Mountains, the pestles were probably picked up long ago by collectors (illegal, as this is Federal land).
In the Southwestern U.S., mortars were probably used to process mesquite beans. At higher elevations, they were employed for grinding acorns. While it's possible that Apaches used the mortars, it's unlikely that they made them.  They probably date much earlier than the Apache presence in the area.  In fact, the rock (probably monzonite) is very hard, and the depth of the hole indicates considerable antiquity, probably in the thousands of years. Photo taken in May of 2001.

Cornudas Mountain coordinates: 32.093163, -105.51636

Earth Observatory Image