Milling Stone or Metate
Coarse volcanic rock
Circa: Prehistoric Period 10,000 B.C. – AD 1850
H 12cm, D 18cm
Lake Mead National Recreation Area, LAKE 3481
A metate is a milling stone used in conjunction with a stone mano to grind foodstuffs, such as corn kernels into a paste or flour before cooking.
References:
National Park Service
http://www.nps.gov/meve/forteachers/artifactgallery_manometate.htm