Bedrock mortar

A bedrock mortar (or BRM) is a set of man made circular depressions in a rock outcrop or naturally occurring slab, used by early peoples for grinding of grain, acorns or other food products. [ [http://www.heritageedu.com/glossary.htm#bedrock Archaeology online glossary] ] There are often a cluster of a considerable number of such holes in proximity indicating women gathered in teams to conduct food grinding in prehistoric cultures. Correspondingly the alternative name gossip stone is sometimes applied, indicating the social context of the food grinding activity. Typical dimensions of the circular indentations are approximately 12 centimeters in diameter by 10 centimeters deep, although a considerable range of depths of the cavities have been documented . [ [http://www.indiana.edu/~e472/cdf/suggest/techniques/ "Discovering Prehistoric Sites:Objective and Subjective Survey Techniques", Daniel G. Foster, Brian D. Dillon, and Linda C. Sandelin, California Department of Forestry and Fire Protection, June 13, 2005] ] The bedrock mortar has been identified in a number of world regions, but has been particularly intensely documented in the Americas. An alternative term for the bedrock mortar site is bedrock milling station.

Example locations of occurrence

*Along the north banks of the middle reaches of the Merced River in Mariposa County, California, USA [G. Deghi, J. Buxton et al., Earth Metrics, "Environmental Impact Report for the Saxon Creek Water Project, Mariposa County, California", published by the County of Mariposa Planning Department and Mariposa County Water Agency, Report 10298, May, 1990]
*In northern Mexico within the Sierra Tarahumara of Southern Chihuahua [ [http://www.mexicohorse.com/Cultural%20continuity.htm C. Melvin Aikens, "Cultural Continuity in the Sierra Tarahumara of Southern Chihuahua, Mexico", June 2003 ] ]
*The Upper Cumberland Plateau of Tennessee, USA
*The Cueva de los Corrales region of northwestern Argentina [M. Del Pilar Babot, María C. Apella, "Maize and Bone: Residues of Grinding in Northwestern Argentina", Archaeometry, Volume 45 Issue 1 Page 121-132, February 2003]

ee also

*Grinding slab
*Mano
*Metate

Line note references