Beads made from Gulf of California dwarf olive shells (Olivella dama) have recently been identified from the Spiro site in eastern Oklahoma. This is the first evidence from Spiro of culture contact to the west. The beads, previously identified as Olivella nivea, are important because O. dama originates in the Gulf of California while O. nivea is from the Gulf of Mexico. An overview of Olivella beads from Plains sites reveals a mixture of shell beads originating from the Gulf of Mexico, the Pacific Ocean, and the Gulf of California. The presence of western Olivella beads at Spiro and other Plains sites supports an intensification of trade between Puebloan and Plains peoples during Late Prehistoric times at about A.D. 1400 or slightly earlier, but there is no evidence for strong cultural ties to the west. Olivella beads occur at sites east of the Mississippi River, and these need to be identified to determine coast of origin.
Reports of explorations and surveys, to ascertain the most practicable and economical route for a railroad from the Mississippi River to the Pacific Ocean. Made under the direction of the secretary of war, in 1853-[6] ...