Cup Stones

A common stone artifact found throughout most of Oklahoma is the cup stone. These are usually unshaped stones, commonly about the size of one's fist, with rather flat surfaces which have small cups or pits on the flat areas. They are usually made of sandstone, limestone, or some sedimentary type of rock. There is much variation in cup stones, however, with the presence of the cupped area being about the only common characteristic. They range from small stones with one or more cups, usually on opposite surfaces of the stone, to larger blocks or slabs of stone that may have several cups present. There is also much variation in the shape of the cups themselves. Some are shallow bowl-shaped cups, others are almost conical in form, while others may be irregular and not so well defined in outline. There is also much variation in the cup size although most examples will fall between 20 mm and 30 mm in diameter. The depth of the cup is partly a function of the diameter but is normally less than 10 mm (Figure 21).

Similar cups or pits are often found around the margins of milling slabs or on bedrock outcrops close to habitation areas. The cups may also occur on broken stone artifacts such as manos or mullers where the broken specimen was retained for service as anvils or hammerstones. Many cup stones were also used as hammers tones as indicated by crushed or battered surfaces around the sides and edges. The purpose of the cup stone remains uncertain in many instances.


Most of them, however, are the result of using the stone for an anvil, the cup having been formed by attrition of the anvil stone as a consequence of utilizing the same spot continuously over a period of time. A cup would have been produced on the anvil in this manner, for example, in the bi-polar knapping process in which pebbles were split or broken, or in the cracking of hard shelled nuts such as walnut or hickory nuts. In either case, the cupped anvil would have helped to stabilize the object of impact. Experiments with bi-polar knapping and nut cracking on an anvil will produce pits or cupped areas similar to many of those present on prehistoric cup stones.

Not all cups found on stones can be accounted for in this manner, however, as some specimens have smoothed cups which would not result from having been used as an anvil. Some of these may have been used as a small mortar for crushing herbs or mixing pigments. An occasional specimen is stained as if it had been used for preparing a red paint.

It seems probable that the cup stone served different purposes; most of them were the result of attrition from use as an anvil stone, but some were purposely produced for some other function. They are clearly a utilitarian artifact which is present from Archaic times onward and are most abundant in the woodland sections of Oklahoma.

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