A
shell ring of the Late
Archaic period has been described at Puerto Hormiga. The Puerto Hormiga ring, found in a marsh, is composed primarily of
clam shells. It has an outside diameter of , a height of about , and the base of the ring mound is to wide. It has a clear interior plaza.
Sherds of fiber-
tempered and sand-tempered pottery, as well as stone tools, were found associated with the shell ring. The earliest have been dated to 3794 BC. The fiber-tempered pottery is "crude", formed from a single lump of clay. Sand-tempered coiled ceramics have also been found at Puerto Hormiga. ==Interpretations==