RODENT GUANO (AMBERAT) FROM CAVES IN ARGENTINA

Deposits of rodent feces cemented together with solidified urine, some times called hyraceum, amberat, guano or midden material, were found i n three caves in northern Patagonia. Some of the material was as much as 4400 years old. It is thought to have been deposited by Andean mice , Phyllotis xanthopygus. In captivity, however, this species produced only a poor quality amberat. Search for such deposits in other arid re gions may make possible, through identification of plant fragments, a comparison of ancient and modern plant communities in South America.