I mention finding a possible Metate or grinding slick now and again, sometimes on (or is it in?) a stone wall. It's another indicator perhaps that the stone wall I'm looking at might be Indigenous in origin.
A list of those sort of stones associated with "grinding" food (or anything else):
- Basin – A shallow bowl-shaped depression in a bedrock outcrop that has been made and/or used for grinding foodstuffs or other materials (see Groundstone below). A certain type of basin found in San Diego County mountains is known as a “Cuyamaca Oval” for its elongated oval shape. Compare to “Metate”, “Mortar”, and “Slick” below.
- Metate – A “Metate” is a large flat rock used as a base-stone for grinding various substances (see “Mano” and “Groundstone” above). Portable metates are often shaped into rounded forms, but can simply be unshaped slabs of stone. Bedrock metates are usually called “slicks” (see below) or “basins” (see above) depending on how much of a depression has been formed.
- Millingstone – The term Millingstone originally was used to refer to stone tools used for grinding, such as Manos and Metates, however, because these tools are often used for more than “milling” grains, the term Groundstone (or ground stone) is often preferred (see above).
- “Millingstone” is also the name of a time period dating from between approximately 9,000 and 5,000 years before present. It is characterized by the presence of abundant manos and metates (see above).
- Mano – “Mano” is a Spanish term meaning “hand.” Archaeologists use the term “Mano” or “Handstone” to refer to a stone tool used to grind nuts, seeds, clay, or other materials (also see “Metate”). It is typically flattened on one or two faces from grinding use and fits easily into the hand. It is used in a circular or back and forth motion. Also see “Groundstone” above.
- Mortar – A shallow to deep, circular hole or depression in a bedrock outcrop that is used as a container for pounding, pulverizing, and/or grinding acorns, seeds, plants, pigments, or other materials and foods with the use of a pestle (see below). Portable mortars that are shaped on the outside are often classified as stone bowls.
- Slick / Grinding Slick – A flat, horizontal area of a rock or outcrop that has been worn smooth by grinding or processing materials with a handstone or mano. Slicks have very little or no depth. Also see “metate” and “groundstone” above.
Definitions from: http://www.sandiegoarchaeologicalsociety.com/?page_id=282
WENDELL, MA - November 21, 1012 - Neill Bovaird of Wolf Tree Programs collects and cooks acorns from Black Oak trees to boil and make into flour. The flour is very dense and is usually blended with other flours for baking. Photo by Beth Reynolds
New Flickr "Metate" Folder: https://www.flickr.com/photos/34580529@N04/albums/72157656888393573