The only marine mollusk listed for 22 samples from beds on Whitewater Creek and San Pedro River is a fragment of Olivella identified as Olivella pedroana Conrad: “A marine species of the Gulf of California and the Pacific coast from California southward. Only one fragment found. It is possible that this might have been used as an ornament.“ This specimen is from the lowest or Sulphur Spring stage of the Cochise culture, which has yielded certain extinct mammals.

“The problem of the route of spread [of the Cochise people] is raised by the occurrence with the Sulphur Spring artifacts at Double Adobe (bed b, Fig. 12) of a shell fragment of the marine gastropod Olivella pedroana Conrad, which postulates that the Chochise people had contact with the west coast.“