It was not until Pueblo times that the Atlantic trade reached the southwest when the Pacific trade was also at its zenith.
For years archaeologists were puzzled by the absence in New Mexico of residue shell material which ought to be present wherever bracelets of the Glycymeris clam appear. Not until 1930 were the hundreds of ancient manufacturing centers discovered along the Sonora coast of the Gulf of California. There the early Indians sawed out patterns and ground down the clams to a smooth finish. The existence of this industry in the areas where the clams live illustrates one of the fundamental problems of prehistoric trade where beasts of burden were unknown and all goods were carried on men’s backs. The finished product was not only much lighter, but also brought a better price.
The Mohaves used a trade route from the Pacific Coast in the vicinity of Los Angeles across the mountains into Nevada and Utah, and they perhaps have the rightful claim to the title of the “Phoenicians of the West.” Several routes extended from the Sonora coast of the Gulf of California up to the Gila basin to Pecos in northwestern New Mexico. Around this area there is evidence that the Pacific and Atlantic trade converged during Pueblo times. It is quite likely that Pecos was a trading pueblo between the southwestern peoples and the plains tribes.
In the midwest of the United States an entirely separate trade route existed from the Mound Builders of Illinois (Cahokia group) south to the Gulf of Mexico. Among the mounds of these prehistoric people the Cameo Helmet Shell (Cassis), the Fighting Conch (Strombus) and the Apple Murex Shell have been discovered—all species from southern Florida or the warmer waters of the Gulf of Mexico.
In recent times, the dispersal of mollusks has been little short of spectacular, particularly so if we may mention in this connection the many large collections that have been assembled in natural history museums. For the last 200 years there has been a steady flow of specimens to these study collections from all lands. Probably the largest mollusk collection in existence, that housed in the United States National Museum in Washington, contains over 9,000,000 specimens and represents about 45,000 kinds. This collection is the result of a century of labor on the part of thousands of ardent enthusiasts who collectively have stooped to pick up mollusks in over 100,000 localities throughout the world.
Added to the scientific traffic of material among dozens of natural history institutions, is the constant and spirited exchange of specimens among thousands of private shell collectors. It is little short of miraculous that in a small Connecticut town one can find in an amateur collection a rare, ivory-like Thatcheria shell from 200 fathoms in Japanese waters or a 200-pound valve of the giant clam from the Great Barrier Reef of Australia. In a small cabinet of land mollusks in Boonton, New Jersey, you may find a giant Afri-
