Bedrock mortar in a rock shelter on the Upper Cumberland Plateau

A bedrock mortar (BRM) is an

anthropogenic Anthropogenic ("human" + "generating") is an adjective that may refer to: * Anthropogeny, the study of the origins of humanity Counterintuitively, anthropogenic may also refer to things that have been generated by humans, as follows: * Human im ...

circular depression in a rock

outcrop An outcrop or rocky outcrop is a visible exposure of bedrock or ancient superficial deposits on the surface of the Earth. Features Outcrops do not cover the majority of the Earth's land surface because in most places the bedrock or superficial ...

or naturally occurring slab, used by people in the past for grinding of

grain A grain is a small, hard, dry fruit (caryopsis) – with or without an attached hull layer – harvested for human or animal consumption. A grain crop is a grain-producing plant. The two main types of commercial grain crops are cereals and legum ...

acorn The acorn, or oaknut, is the nut of the oaks and their close relatives (genera ''Quercus'' and '' Lithocarpus'', in the family Fagaceae). It usually contains one seed (occasionally two seeds), enclosed in a tough, leathery shell, and borne ...

s or other food products. There are often a cluster of a considerable number of such holes in proximity indicating that people gathered in groups to conduct food grinding in

prehistoric Prehistory, also known as pre-literary history, is the period of human history between the use of the first stone tools by hominins 3.3 million years ago and the beginning of recorded history with the invention of writing systems. The use of ...

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 . The bedrock mortar has been identified in a number of world regions, but has been particularly intensely documented in the

Americas The Americas, which are sometimes collectively called America, are a landmass comprising the totality of North and South America. The Americas make up most of the land in Earth's Western Hemisphere and comprise the New World. Along with th ...

. An alternative term for the bedrock mortar site is bedrock milling station.

Bedrock metate

A bedrock mortar should not be confused with a bedrock

metate A metate (or mealing stone) is a type or variety of quern, a ground stone tool used for processing grain and seeds. In traditional Mesoamerican cultures, metates are typically used by women who would grind nixtamalized maize and other organic ma ...

, which is a flat,

trough Trough may refer to: In science * Trough (geology), a long depression less steep than a trench * Trough (meteorology), an elongated region of low atmospheric pressure * Trough (physics), the lowest point on a wave * Trough level (medicine), the l ...

-shaped depression often found with bedrock mortars.

Example locations of occurrence

*Southern

Arizona Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a state in the Southwestern United States. It is the 6th largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona is part of the Fou ...

: In the Santa Catalina, Santa Rita, Rincon, Sierrita, and

Tucson Mountains The Tucson Mountains (O'odham: Cuk Doʼag) are a minor mountain range west of Tucson, Arizona. The Tucson Mountains, including Wasson Peak, are one of four notable mountain ranges surrounding the Tucson Basin. The Santa Catalina Mountains lie ...

, and also in rock outcroppings in the valleys *Along the north banks of the middle reaches of the

Merced River The Merced River (), in the central part of the U.S. state of California, is a -long tributary of the San Joaquin River flowing from the Sierra Nevada (U.S.), Sierra Nevada into the San Joaquin Valley. It is most well known for its swift and st ...

Mariposa County, California Mariposa County () is a county in the U.S. state of California. As of the 2020 U.S. Census, the population was 17,131. The county seat is Mariposa. It is located in the western foothills of the Sierra Nevada mountains, north of Fresno, east of ...

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

*In Santa Barbara and

San Luis Obispo San Luis Obispo (; Spanish for " St. Louis the Bishop", ; Chumash: ''tiłhini'') is a city and county seat of San Luis Obispo County, in the U.S. state of California. Located on the Central Coast of California, San Luis Obispo is roughly halfwa ...

counties on the California Central Coast *In northern

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

within the Sierra Tarahumara of Southern Chihuahua *The Upper

Cumberland Plateau The Cumberland Plateau is the southern part of the Appalachian Plateau in the Appalachian Mountains of the United States. It includes much of eastern Kentucky and Tennessee, and portions of northern Alabama and northwest Georgia. The terms "Alle ...

Tennessee Tennessee ( , ), officially the State of Tennessee, is a landlocked state in the Southeastern region of the United States. Tennessee is the 36th-largest by area and the 15th-most populous of the 50 states. It is bordered by Kentucky to th ...

, United States *Inside many rock shelters in

Menifee County, Kentucky Menifee County is a county located in the U.S. state of Kentucky. As of the 2020 census, the population was 6,113, making it the fifth-least populous county in Kentucky. Its county seat is Frenchburg. The county is named for Richard Hickman M ...

, United States *The Cueva de los Corrales region of northwestern

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...

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

Gallery

File:Garrod's terrace el-Wad.jpg,

Natufian The Natufian culture () is a Late Epipaleolithic archaeological culture of the Levant, dating to around 15,000 to 11,500 years ago. The culture was unusual in that it supported a sedentary or semi-sedentary population even before the introduction ...

bedrock mortars at

Mount Carmel Mount Carmel ( he, הַר הַכַּרְמֶל, Har haKarmel; ar, جبل الكرمل, Jabal al-Karmil), also known in Arabic as Mount Mar Elias ( ar, link=no, جبل مار إلياس, Jabal Mār Ilyās, lit=Mount Saint Elias/Elijah), is a c ...

, Israel. File:Muidu bedrock mortars.jpg,

Maidu The Maidu are a Native American people of northern California. They reside in the central Sierra Nevada, in the watershed area of the Feather and American rivers. They also reside in Humbug Valley. In Maiduan languages, ''Maidu'' means "man." ...

bedrock mortars in northern California. File:AnzaMorterosByPhilKonstantin.jpg, Bedrock mortars at the

Anza-Borrego Desert State Park Anza-Borrego Desert State Park (, '' AN-zə bə-RAY-goh'') is a California State Park located within the Colorado Desert of southern California, United States. The park takes its name from 18th century Spanish explorer Juan Bautista de Anza and ...

in southern California. File:Acorn grinding stone-750px.jpg, Bedrock mortars used to grind

s in California. File:Indian_Kitchen_Bedrock_Mortars_2013.jpg,

Hohokam Hohokam () was a culture in the North American Southwest in what is now part of Arizona, United States, and Sonora, Mexico. It existed between 300 and 1500 AD, with cultural precursors possibly as early as 300 BC. Archaeologists disagree about ...

bedrock mortars at Indian Kitchen, Arizona. File:Huerfano Butte Arizona Bedrock Mortars Number 1.jpg, Bedrock mortars at

Huerfano Butte Huerfano Butte (; ) is a volcanic plug or hypabyssal plug located north of Walsenburg in Huerfano County, Colorado, United States. Named ''Huérfano'' (English: orphan) by early Spanish explorers, it rises above the south side of the Huerfano ...

. File:Huerfano_Butte_Arizona_Bedrock_Metate.jpg, A close up view of a bedrock metate at Huerfano Butte.

Line note references

{{DEFAULTSORT:Bedrock Mortar Food preparation utensils Archaeological features Food grinding tools

Bedrock metate

Example locations of occurrence

Gallery

See also

Line note references