These two obsidian flakes were recovered from the Grassroots site, 14SN307, an Early Ceramic camp site in Sherman County. In 2005, they were sent for xray-florescence (XRF) testing, a chemical and elemental analysis that determines where material, such as these two obsidian flakes, came from originally. One piece was determined to be Valles Rhyolite from the Cerro del Medio member and the other to be Cerro Toledo Rhyolite from the Obsidian Ridge member, both places found in the Jemez Mountains in New Mexico. Thus XRF studies help archeologists to learn about ancient trade patterns.
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