Cupules are widely believed to be the world’s most common rock art motifs, found in huge numbers on every continent except Antarctica.
They occur commonly in groupings that may number several hundred. They may be arranged in geometric formations, such as aligned sets, or occur in unstructured, random groups.
Surprisingly little is definitely known about the purpose or significance of cupules.
Many meanings or purposes have been suggested.
Typically, cupules were created by direct percussion, i.e. using hand-held hammer-stones. There is considerable bias against such forms of rock art, which have often been ignored by researchers, misunderstood or explained as utilitarian rock markings.
Cupules are among the least investigated forms of rock art. They have been subjected to a variety of over-interpretations based on very inadequate evidence, and there has been an incredible number of misidentifications.
Archaeologists have not presented a scientifically based, or even plausible, explanation or interpretation of the rather strange behavior pattern manifested in cupules.
Specific boulders bearing collections of cupules were visited by Pomo women to conduct fertility ceremonies.
These rituals, intended to lead to conception, involved the collection of the ‘fertilizing’ dust created in pounding the cupules to achieve pregnancy through the rock’s magical essence.
The Klamath of southern Oregon are said to have renewed cupules in order to summon the wind to change the weather. Similarly, the Shasta of California sought to influence the weather.
They pounded cupules to induce rainfall and wind.
One further explanation for cupules are as Hupa ‘calendar stones’.
Contemporary Hupa believe the stones to have some astronomical role.
It has been proposed that this tradition dates from ‘pre-Hokan’ or Paleo-Indian times, i.e. from between 12000 and 9000 years ago.
Cupules are significantly under- represented in the published record and have been widely ignored in the recording of rock art. The published record on the study of work traces in cupules can fairly be described as pitiful.
The most commonly mentioned archaeological interpretations of cupules can be grouped into a number of classes, based on purported uses.
1. The preparation of paints
2. Unspecified or specified cultic or magic rituals
3. The pounding of medicines (mineral or plant), pigments or spices
4. The placement of offerings, including human blood and semen.
5. The depiction of star constellations.
6. The map-like depiction of topographic elements of nearby landscapes.
7. Geophagy (ingestion of mineral dust).
8. Board games.
9. A symbolism that is no longer recoverable.
Other East Bay areas where we have encountered cupule rocks include:
Upper Welch Creek, Stromer Spring, West Ohlone Rocky Ridge, Mallory Creek, Round Valley, Marsh Creek, Mira Vista Park, Canyon Trail Park.