Ruth Dickau, from the University of Exeter (England), unearthed 12 unusual stones in the back of the small, prehistoric Casita de Piedra rock-shelter near the town of Boquete in 2007. The cache represents the earliest material evidence of shamanistic practice in lower Central America. Charcoal found underneath the cache was dated to 4,800 years ago, and above the cache to 4,000 years ago. "The fact that the stones were found in a tight pile suggests they were probably deposited inside a bag or basket, which subsequently decomposed," Dickau said.
     They consist of a small dacite stone fashioned into a cylindrical tool; a small flake of white, translucent quartz; a bladed quartz and jarosite aggregate; a quartz crystal aggregate; several pyrite nodules that showed evidence of use; a small, worn and abraded piece of chalcedony; a magnetic andesite flake; a large chalcedony vein stone; and a small magnetic kaolinite stone naturally eroded into an unusual shape.
     Consulting geologist Stewart Redwood says, "A fascinating aspect of this find is that these are not ordinary stones but are rocks and crystals commonly associated with gold deposits in the Central Cordillera of Panama and Central America. However, there are no gold artefacts in the rock-shelter, and there's no evidence that the stones were collected in the course of gold prospecting as the age of the cache pre-dates the earliest known gold artefacts from Panama by more than 2,000 years."
     Anthony Ranere, from Temple University in Philadelphia (USA), first identified and excavated Casita de Piedra in the early 1970s, finding it had been repeatedly occupied over thousands of years and used for a variety of domestic activities.
     Dickau's group discovered it was first occupied more than 9,000 years ago. The people practiced small-scale farming of maize, manioc and arrowroot, collected palm nuts, tree fruits and wild tubers, and probably hunted and fished.

Edited from EurekAlert! (14 January 2013)