You may remember Henry W. Henshaw as the author of Animal Carvings from Mounds of the Mississippi Valley . In this book he  questioned the authenticity of the famous elephant pipes and this eventually led to what became known as The Davenport Conspiracy. 

Here we have him describing the famous perforated stones found in California.  By comparing similar stones in other cultures, as well as eyewitness accounts, he poses credible explanations of their use.  This booklet is not limited to the archaeology of California as perforated stones are also found in many other areas of the country. The descriptions of possible uses include: digging stick weights, gaming, weapons and ceremonial objects