Cupstone facts for kids

Cupstones, also called anvil stones, pitted cobbles and nutting stones, among other names, are roughly discoidal or amorphous groundstone artifacts among the most common lithic remains of Native American culture, especially in the Midwestern United States, in Early Archaic contexts. The hemispherical indentation itself is an important element of paleoart, known as a "cupule". Cup and ring marks are also common in the Fertile Crescent and India, and later in the Mediterranean, Atlantic, and Alpine regions of Europe, sometimes associated with complex petroglyphs or megalithic monuments.

Etymology

One encyclopedia of archaeology treats "pitted stone", "cupstones", and "nutting stones" as synonyms and says that they "may have been formed by cracking nutshells, though this activity lacks adequate confirmation through ethnographic examples or published experimentation."

Purpose

These objects have received little study, perhaps because edged tools and weapons have more intrinsic interest to private collectors, but closer study of them might reveal something of domestic practices and toolmaking technology. There is no agreement upon their purpose or purposes, which may have included the processing of food, medicine or pigments, storage, arrow-production or fire-drilling. As such, they could represent a primitive form of mortar and pestle. The age of these man-made structures is difficult to ascertain, but generally they are believed to have been produced in the Bronze Age and Upper Paleolithic although some, for example in North America and Europe, were generated at a later date.

Visually, they may resemble omarolluks, a naturally occurring feature of sedimentary rock occurring exclusively in the Belcher Islands, an archipelago accounting for 0.25% of Hudson Bay, whence they are thought to have been spread by glaciers.

Distribution

Similar objects can be found on all continents except Antarctica. They are associated with Celtic Europe, prehistoric Australia, Borneo and the Middle East. Some of the earliest cupules can be found at the Bhimbetka cave site in India, dating to 290,000-700,000 BCE, but in Europe they do not pre-date the most recent cold phase (the Würm or Weichselian glaciation). Some scholars insist the items are "false" artifacts, that is, their form results from natural processes rather than human activity. However, no one has yet described processes that might both produce such effects and also explain the distribution of the effects and the objects. Certainly air-bubbles in stone, broken open and eroded, could produce some of these phenomena. The objects are familiar in Illinois, Ohio, Indiana, Arkansas, Kentucky, Tennessee, Alabama and Mississippi, and occur elsewhere as well.

The pattern, size and number of concavities is not predictable, nor is material—impressions are found in soft sandstone and hard granite. Cupstones may exhibit a mixture of large and small indentations, perhaps indicating multiple uses over a considerable span of time. Indentations range from barely visible 1/16" to 6". Examination under magnification suggests the impressions were at least in some cases formed by rotary grinding, particularly in softer rocks. In most cases, archeological evidence of cupstones on hard rock surfaces and monoliths indicates that they were created by direct percussion with rock hammers. Typical impressions are of the simple pit type, though some cavities have been excavated to produce an opened-sphere type of pocket, by means and for reasons unknown. Very large specimens weighing several tons and with dozens of impressions several inches across are thought to be cult objects; they have been found throughout the Mississippi Valley.

Historic accounts

There are several ethnographic accounts of the Native use of nutting stones in the historic times. One account says "the Virginia Indians in 1587 tells us that each household had stones for cracking nuts and for grinding shell and other materials." It goes on to say that "This statement would doubtless be equally true if applied at that time to almost any tribe inhabiting the section east of the Mississippi."

In Hawaii, cup and ring marks are associated with petroglyphs, and those occurring in the boundary regions of Apuki and Puna lands have been used as depositories for a child's navel cord, a custom also observed in other Polynesian peoples.

Omars

Nutting stones can be very similar in appearance to omars. Omars are naturally formed stones that have hemispherical bubbles in them.