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GRINDING STONES
WORLDWIDE
est. 30,000 YEARS AGO TO PRESENT DAY

PAGE 1 OF 1 PAGES
COPYRIGHT MAY 31, 2014 PETER A. BOSTROM
Abstract image of metates and girl demonstrating use of.
TROUGH METATES
BANDELIER NATIONAL MONUMENT---NOV. 12, 1976
NEW MEXICO

Abstract image of metates.

ABSTRACT
GRINDING STONES
WORLDWIDE

est. 30,000 YEARS AGO TO PRESENT DAY

    This article discusses grinding stones worldwide and illustrates and describes several examples of grinding stones from Indonesia, United States, and Mexico. Grinding stones were mainly used for milling plant seeds into flour or meal. Historic accounts and skeletal analysis indicate they are tools that were used by women. Grinding stones have been in continuous use in some areas of the world for at least 30,000 years. The development of starch residue analysis has been one of the most interesting new tools that archaeologists have used to identify the types of plants that were last processed.

    "Arguably, among the most important tools in ancient Mesoamerican houses were the mano and the metate, a pair of implements used to grind food. Their abundance in the archaeological record is evident in excavation reports from this region."--------2011, Michael T. Searcy, "The Life-Giving Stone, Ethnoarchaeology Of Maya Metates" p. 1.
    "Grinding stones can be difficult to transport (because of their size and weight from find site to museum storage), and they quickly fill up laboratory and storage space. I have seen metate upon metate carelessly stacked in a repository in Mexico, and due to their capacity to overwhelm storage space, they often serve secondary purposes such as doorstops in museums."------2011, Michael T. Searcy, "The Life-Giving Stone, Ethnoarchaeology Of Maya Metates" p. 5.
    "Extraction of raw material by both the Poqomam and K'iche" metateros (in Guatemala) entails digging down to the large boulders, underneath many feet of soil in some cases. Gabriel Pascual of Jilotepeque showed me where he and his son had dug two and a half meters before reaching a basalt boulder."--------2011, Michael T. Searcy, "The Life-Giving Stone, Ethnoarchaeology Of Maya Metates" p. 39.
     "Metates grinding stones (on the Maya site of Copan, Honduras) were found in every residence type sampled, regardless of the household's projected status."----1983, Mary Louise Spink, "Metates As Socioeconomic Indicators During The Classic Period At Copan, Honduras," (A Thesis In Anthropology), p. iii.
    "In North America, the use of the metate-mano milling stones is confined mainly to Mexico and the Southwestern United States where varieties of soft-shelled flour corn are suitable for this method of grinding. The hard-coated, flint corn of the eastern coast necessitated direct pounding with a pestle in a stone or wooden mortar"
---------1979, Frank W. Eddy, "Metates & Manos. The Basic Corn Grinding Tools Of The Southwest," p. 4.
    "The people of Ohalo II, a remarkable waterlogged site in Israel that dates to around 23,000 years ago, took seed processing a step further, they ground grass seeds (wild barley) into meal using massive stones."---------2011, Kristen J. Gremillion, "Ancestral Appetites: Food In Prehistory, p. 41.
    "Although grinding technology appears in early prehistory, its development is quite late and seems to be associated with contexts of transition from hunter-gatherer to farming cultures."--------2001, Laure Dubreuil, "Functional Studies Of Prehistoric Grindingstones, A Methodological Research," Bulletin du Centre de Recherche Francais A Jerusalem, p. 73.
     "Manos and metates are still used and sold in markets today throughout Middle America, and many people believe that food is properly prepared or tastes better only if these traditional stone tools are employed."---------2000, Joel W. Palka, "Historical Dictionary Of Ancient Mesoamerica," p. 73.
   "In most recorded cultures, it has been women who performed this task (of grinding grain)."---------2006, Adam Lucas, "Wind, Water, Work: Ancient And Medieval Milling Technology," p. 9.

 Milling stones from Asia and southwestern U.S.
 
GRINDING STONES
WORLDWIDE

est. 30,000 YEARS AGO TO PRESENT DAY

     Grinding stones represent one of the largest types of stone tools that were used by ancient cultures. They are actually a primitive form of machine that requires two parts to operate, a hand-held mano and a grinding plate. Grinding stones were every bit as important as a modern appliance might seem today. Their level of importance is inferred in Searcy's book title, "The Life-Giving Stone" in which he quotes a Maya women, "The metate is the reason we are alive." Although fewer of them are used with each passing day, grinding stones were once one of the most important tools used around the world to process food.

Manos and metates for sale in a market in Mexico.
PHOTO CREDIT LITHIC CASTING LAB'S COLLECTION OF ORIGINAL IMAGES
CLICK ON PICTURE FOR LARGER IMAGE
MANO AND METATE MARKET
MEXICO CITY, MEXICO

    This picture shows a modern-day market in Mexico City where metates and manos can still be purchased. Although the use of stone corn grinders are fading, they are still being used by many people living mainly in rural areas.

     Recent studies, in Mesoamerica, have provided some insight into the average amount of time that women have spent grinding corn each day. Grinding corn on a metate with a two handed mano is labor intensive. Some households divided the work with different female members of the family. Girls traditionally learned how to use a metate at a very young age. An Aztec manuscript illustrates a mother teaching her thirteen year old daughter to grind maize with a metate. Searcy (2011, 86) averaged the daily grinding time estimates from five researchers (Chinas 1973, Foster 1979, Lewis 1949, Smith 2003, and Vogt 1970). The average daily time estimates vary widely, from a minimum of three hours to a maximum of eight hours. Some factors that would change the grinding time from person to person are age, proficiency, and type of grinding stone used. Searcy's study of four Maya women in Guatemala resulted in an average time of 4.8 hours of grinding time per day for a family of five. His data shows that, "grinding maize was an activity that potentially occupied a third of the day of Mesoamerican women."

Navaho women grinding corn with a metate and mano.
PHOTO CREDIT, ED SHAW, LITHIC CASTING LAB'S COLLECTION OF ORIGINAL IMAGES
NAVAHO WOMAN GRINDING CORN
NEW MEXICO (1960's)

    This picture was taken sometime in the 1960's at one of the pueblos in New Mexico. It shows a Navaho woman demonstrating the use of a metate and mono. One of the baskets in front contains processed corn that's been ground to a flour-like consistency. An extra flat-style mano is leaning against the front of the grinding box.

     In the past, there has been some concern that grinding stones haven't received the attention they should. But, in recent years, there does seem to be more interest in them, especially in the area of starch analysis. One of their drawbacks for study has been their large bulky size. For example, two of the examples pictured in this report from Illinois together weigh 122 pounds. So they are difficult to transport and store. In fact, Searcy (2011), comments how they've been described as a pain in the backside. He reports that they have often ended up as doorstops in museums.


SIMPLE GRINDING STONE & MANO
MADISON COUNTY, ILLINOIS

    Both of these grinding tools were found on a site in Madison County, Illinois. The lower grinding plate is slightly concave from the action of grinding. Both of these tools show little or no shaping except for grinding wear. The earliest grinding stones are simple unaltered pebbles. Hunter/gathers began using naturally shaped stones, with a flat surface. One handed manos are the earliest forms of upper grinders used.

      The best tool that archaeologists currently have to study grinding stones is the ability to identify different types of starch by microscopic analysis of surface residue. Rough grinding surfaces are ideal locations for recovering samples of plant residues. It's been known for 150 years that starch granules can be identified to specific plants. Australia, China, Ecuador, Japan, New Guinea, and Israel are some of the countries reporting the use of starch identification on ancient grinding stones. Starch granules have been identified from a wide range of different types of plants, such as, Manioc, banana, water chestnut, palm, and walnut plus the more common cereal grains like corn, barley, wheat, and oats. In Queensland, Australia starch from grinding stones were identified as two different kinds of walnut. In Ecuador, the identification of maize starch on grinding stones date the domestic use of corn to between 5300 to 4960 cal years before present. In northern China at the Shizitan site cluster, 23,000 to 19,500 year old grinding stones contained starch from grasses, beans, yams, and snakegourd roots. Plant starch residue has been reported from grinding stones as early as 30,000 years ago.

Grinding stones and mano from Indonesia.
PHOTO CREDIT LITHIC CASTING LAB'S COLLECTION OF ORIGINAL IMAGES
COMPUTER ALTERED IMAGE

GRINDING STONES
INDONESIA

    Both of these grinding plates and mano were collected somewhere in Indonesia and were made by craftsmen who specialized in making grinding tools. They are believed to be several hundred years old.

    Grinding stones were mainly used to process food. But evidence shows they were also used to process non-food items such as clay for ceramic containers, temper for clay used as a binder, paint pigments and lime. Nonetheless, food processing was still their main purpose. The Maya used them to grind Maize (corn) but also use them for many other types of foods such as cacao, beans, squash seeds, tomatoes, coffee, sugar, salt, and chilies.

Metates from southwestern U.S.
PHOTO CREDIT LITHIC CASTING LAB'S COLLECTION OF ORIGINAL IMAGES
TROUGH METATES
BANDELIER NATIONAL MONUMENT--1976
NEW MEXICO

    These three excellent examples of trough metate grinding stones were found on the site of Bandelier National Monument. Their principle use was for grinding corn. They were made sometime between 1150 and 1550 by early Pueblo people. Trough metates are reported to be the most efficient style of grinding stone.

    The use of grinding stones, to process food, predates the development of farming. People who were living a hunting and gathering lifestyle began to develop traditional food grinding technologies by 30,000 years ago. A grinding stone made of basalt was found on the ancient site of Abu-Hureyra in Syria that dates to about 11,200 years before present. The Ohalo II site in the sea of Galilee in Israel produced a basalt grinding stone that dates to 23,000 years ago. In Australia the oldest grinding stones are reported from Cuddie Springs, in New South Wales, at 30,000 years ago. Another site, in southern Japan called Nishitaragasako, produced grinding stones that date to sometime between 32,000 and 29,000 years ago.

Metates, monos, and morters from southwestern U.S.
PHOTO CREDIT LITHIC CASTING LAB'S COLLECTION OF ORIGINAL IMAGES
CLICK ON PICTURE FOR LARGER IMAGE
METATES, MANOS, & MORTARS
CASA GRANDES
NORTHWESTERN MEXICO
STATE OF CHIHUAHUA

    This picture was taken in 1973 on the ancient site of Casa Grandes in northwestern Mexico. The artifacts appear to be either metates, manos, pestles, and mortars. Most of these tools were used to process food by crushing and grinding.
    The Casa Grandes site is one of the largest and most complex archaeological sites in the region. The earliest settlement dates to about 1130. The site then developed into multistoried dwellings by about 1350 and was abandoned by 1450.

    Grinding stones were developed in different forms all over the world. But the basic technique was fundamentally the same everywhere. The process involves two stones, a lower stone and an upper stone. The lower stone was either small enough to be portable or incorporated into a layer of bedrock. Some of the names they have been referred to are grinding stones, quern stones, grinding slabs, milling stones, metates, morahs, and bedrock metates. The upper stone was either small and held in one hand or large and used with both hands. They are referred to as hand stones and manos. Roller pestle is a name often used by collectors. A third style of grinder consists of two round discs that is turned by hand on a spindle and is called a rotary quern.

Grinding stone from Illinois.
CLICK ON PICTURE FOR LARGER IMAGE
GRINDING STONE
SOUTHERN ILLINOIS

      This very large grinding stone was found on a site in southern Illinois, possibly in Calhoun County. It's one of the largest stone tools that has been found in this area. It was apparently used for multiple purposes. The long narrow groove on one side may have been used to grind axes. But a large shallow concave area on the other side may have been used for grinding food materials. The small circular concavities along the edges may have been used to crack nuts. This sandstone grinder weighs 76 lbs. and measures 20 3/8 inches (51.7cm) long, 15 inches (38.1cm) wide and 5 inches (12.7cm) thick.

    Grinding stones were made from many different types of stones depending on local sources. Each type of stone has unique properties that will determine how effective it will be for processing food. For example, a smooth stone will not grind as well as a rough stone and stones that wear quickly will release larger amounts of stone particles into the food that can effect dental health. The most common stones used in Mesoamerica before European contact were granite, rhyolite, andesite, quartzite, sandstone, and limestone. The most common stone used to make modern grinding stones is vesicular (contains tiny holes) granite. Studies show that this type of stone lasts the longest.


LARGE SANDSTONE GRINDING PLATE
SOUTHERN ILLINOIS

    This sandstone grinding stone might be referred to as a basin type grinding stone. It was found on a site in southern Illinois. It shows considerable wear but it still has a lot of use left in it. It's made of fine grained sandstone and measures 16 inches (40.6 cm) long and weighs 46 pounds.

    Metate craftsmen are called metateros in Mexico and in some countries farther south. They quarry the stone and manufacture both the metates and manos. Before the use of explosives, the fire technique was used to quarry the stone. Boulders were fractured by covering them with grass and weeds and setting them on fire. Throwing water on the hot surface fragmented the stone into usable pieces. Hampton (1999) also reported the same quarrying technique by the Dani in Irian Jaya on the Island of New Guinea. Modern-day metateros use metal tools to finish shaping their rough quarried stone into metates. They use various sizes of iron hammers, chisels, and adzes to complete a process that was once accomplished with stone tools.


PHOTO CREDIT LITHIC CASTING LAB'S COLLECTION OF ORIGINAL IMAGES
BANGLADESH WOMAN WINNOWING RICE
PEOPLE'S REPUBLIC OF BANGLADESH (1960's)

    This picture shows a Bangladesh woman in the process of wind winnowing rice. The technique was developed by ancient cultures to separate the grain from the chaff. Bangladesh is the eighth most populated country in the world and is much smaller than Kansas.

     There may not be as many different styles of grinding stones as stars in the sky but, when looking at them in a world perspective, there are a lot of them. Hunter/gathers began using naturally shaped stones, with a flat surface, for grinding. Over time, with the development of farming communities, grinding stones evolved into more complex forms that were manufactured by specialized craftsmen. Most grinding stones did not have any support legs. Support leg styles range from having one large pedestal leg to others that have two wide legs, three legs and some have four. The metate grinding stones of Mesoamerica are rectangular in shape. The most efficient style are the trough metates that have built-in rectangular basins. Studies show they could grind more grain per unit of time than basin or flat/concave metates. The most efficient stone grinders are rotary. They were particularly well established in parts of Asia and Europe. Earliest examples from China date to 2,200 years ago. They are often referred to as rotary querns and consist of two disc shaped stones, one on top of the other. The top stone is turned by hand on a spindle and is perforated with a hole that feeds in the grain.

Monos, and metates from southwestern U.S.
PHOTO CREDIT LITHIC CASTING LAB'S COLLECTION OF ORIGINAL IMAGES
MANOS AND METATES
AZTEC RUINS NATIONAL MONUMENT
NORTHWESTERN NEW MEXICO

    This picture was taken in 1973 of a display of simple grinding stones on the site of Aztec Ruins National Monument. The display appears to be outside for hands-on demonstration. The stones are cemented into place.
    The Aztec Ruins National Monument was established in 1923. It's situated along the Animas River in Aztec, New Mexico. The site contains the ruins of multistoried dwellings built by Ancestral Pueblo Indians. The west ruin once had more than 500 rooms. The site was established sometime in the 12th century and was abandoned by about 1300. The Aztec Ruins site is about 2 miles (3.2 km) long and 1 mile (1.6 km) wide in size.

    It's interesting to note that grinding stones were not the healthiest way to process food. Even though they were generally made from hard igneous rocks like granite or basalt they still wore down. The health issue involves the amount of grit that was introduced into the food being ground. Examination of the skeletal remains of many ancient societies around the world, where stone grinders were used, indicate a damaging effect on dental health. The addition of small stone particles into food produced a secondary grinding effect that wore away tooth enamel. The end result was loss of teeth and other related dental illness at an early age. For example, the teeth of ancient Egyptians show this type of wear pattern. Their average age is reported to have been between 34 and 38 years.

A "worn-out" metate from southwestern U.S.
PHOTO CREDIT 
LITHIC CASTING LAB'S COLLECTION OF ORIGINAL IMAGES
COMPUTER ALTERED IMAGES

"WORN-OUT" TROUGH METATE
PUEBLO BONITO
CHACO CANYON
NORTHERN NEW MEXICO

     This picture shows a trough style metate that was used until the stone was worn through. Wouldn't be interesting to know how many bushels of corn was processed. This picture was taken in 1973 at Pueblo Bonito.
    Pueblo Bonito is the largest building in the Chaco Culture National Historical Park in northern New Mexico. There are an estimated 650 to 800 rooms contained within the site. Pueblo Bonito was occupied by ancestral Pueblo people between the years 828 and 1126. Deforestation and drought are the two main reasons why they only occupied the site for 300 years.

    Another health issue, that grinding stones are responsible for, are wear and tear on the bones of people who have used them.  History records that grinding food was traditionally done by women. The fact that the work was labor intensive is supported by the study of skeletal remains. Skeletons that were studied on the 9,500 year old Syrian site of Abu Hureyra show evidence of osteoarthritis and injuries to the toes, knees, hips and lower back. These types of injuries were almost exclusive to the bones of females. They are thought to have developed from repetitive work in a kneeling position. In-other-words the type of work that would involve the use of grinding stones.

Diorama scene of hogan, Museum of New Mexico.
PHOTO CREDIT 
LITHIC CASTING LAB'S COLLECTION OF ORIGINAL IMAGES
HOGAN DIORAMA
DOMESTIC NAVAJO KITCHEN SCENE
MUSEUM OF NEW MEXICO

    This picture shows a portion of the interior of a Navajo house in New Mexico. The scene is actually a diorama museum display. A common and standard variety of metate can be seen to the left, along with a two-handed mono and, what appears to be, ground corn. These types of simple metates are still in use is some areas today.

    Old taboos and Folkloric beliefs, concerning grinding stones, are still respected in some areas. Some Maya traditions in Guatemala relate such ideas as, "if you leave a metate out under the stars or the moon, it will break" or "if you leave it out in the sun it will become dull." Another belief is that "comparing a metate or mano to other metates and manos will cause them to break." Other examples are, "a man stepping over a metate may cause only female offspring and the reverse for the woman," Eating while grinding may cause illness or injury to children," and "a man touching a metate just after a woman has been grinding may cause only female offspring," These accounts and others suggest a belief that metates have a certain amount of spirit power. Especially when accounts describe the metate as being able to "see" the stars, if it's taken outside the house at night.

Girl demonstrating use of mano and metate.
PHOTO CREDIT GEORGE CRAWFORD & COMPUTER ALTERED BY PETE BOSTROM
GRINDING PLATE & VERY LARGE MANO
BANDELIER NATIONAL MONUMENT---NOV. 12, 1976
NEW MEXICO

    This picture was taken in 1976 at Bandelier National Monument in New Mexico. It shows a demonstration of the use of a metate and a two handed mano, although the mano seems to be almost as large as the demonstrator!

     Although most grinding stones seem worn and rough, in their day they would have been one of the most important tools in a household. They represent a system of processing food that was hard work. In today's modern society, drudgery is the word that comes to mind. But as one Maya woman said, "the metate is the reason we are alive." That pretty much says it all.

"REFERENCES"

1976, Briuer, "Chevelon Canyon And Cayote Creek Pueblo, Arizona, USA, 700-8700BP," American Antiquity.
1979
, Eddy, Frank W., "Metates & Manos. The Basic Corn Grinding Tools Of The Southwest."
1983
, Spink, Mary Louise, "Metates As Socioeconomic Indicators During The Classic Period At Copan, Honduras," (A Thesis In Anthropology).
1984
, Hoffman, Michael A., "Egypt Before The Pharaohs, The Prehistoric Foundations Of Egyptian Civilization.
1999
, Hampton, O. W., "Culture Of Stone, Sacred And Profane Uses Of Stone Among The Dani."
2000
, Palka, Joel W. "Historical Dictionary Of Ancient Mesoamerica."
2001
, Dubreuil, Laure, "Functional Studies Of Prehistoric Grindingstones, A Methodological Research," Bulletin du Centre de Recherche Francais A Jerusalem.
2001
, Misra, V. N., "Prehistoric Human Colonization Of India," Journal Of Biosciences, Vol. 26, No. 4, Indian Academy Of Sciences.
2003
, "On The Earliest Evidence For Rice Cultivation In China," The Institute Of Archaeology, Chinese Academy Of Social Sciences.
2006
, Lucas, Adam, "Wind, Water, Work: Ancient And Medieval Milling Technology."
2006
, Zeder, Melinda A., "Documenting Domestication, New Genetic And Archaeological Paradigms."
2008
, Zarrilli, Sonia, Pearsall, Deborah M., Raymond, J. Scott, Tisdale, Mary Ann, & Quon, Dugane, "Directly Dated Starch Residues Document Early Formative Maize (Zea mays L.) In Tropical Ecuador," Proceedings Of The National Academy Of Sciences, Vo. 105, No. 13.
2011
, Haslam, Michael, "Mountains And Molehills: Sample Size In Archaeological Microscopic-Tool Residue Analysis," Archaeological Science Under A Microscope: Studies In Residue And Ancient DNA Analysis In Honour Of Thomas H. Loy, Australian National University Press Library, Terra Australis 30.
2011
, Field, Judith, Cosgrove, Richard, Fullagar, Richard, & Lance, Braddon, "Starch Residues On Grinding Stones In Private Collections: A Study Of Morahs From The Tropical Rainforests Of NE Queensland," Archaeological Science Under A Microscope: Studies In Residue And Ancient DNA Analysis In Honour Of Thomas H. Loy, Terra Australis 30.
2011
, Searcy, Michael T., "The Life-Giving Stone, Ethnoarchaeology Of Maya Metates."
2011
, Gremillion, Kristen J., "Ancestral Appetites: Food In Prehistory."
2013, Liu, Li, Bestel, Sheahan, Shi, Jimming, Song, Yanhua, and Chen, Xingcan, "Paleolithic Human Exploitation Of Plant Foods During The Last Glacial Maximum In North China," Proceedings Of The National Academy Of Sciences, Vol. 110 No. 14.
2014, Cook, Scott, "Land, Livelihood, and Civility in Southern Mexico: Oaxaca Valley Communities In History"

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