The Biscayne Plain type is a pottery type from south Florida and the Tampa Bay region. The type is a soft and chalky pottery whose core is "dark gray or black and the surfaces buff" (Willey 1949:444).

As describe by Willey 1949:444-445:

Definition as a type: First described by Goggin (1940,1944a). Willey (n.d.) has also described the type under this name. It is identical with St. Johns Plain. The Biscayne Series types were first described from south Florida and the Tampa Bay section; the St. Johns types from northeast Florida.

Ware characteristics: A soft, chalky pottery. Core is dark gray or black and the surfaces buff. Fire mottling is common. Surfaces may be rough or smooth. Hardness 2.5 or less.

Form: Bowls with incurved rims, large, deep, open bowls, collared globular bowls, boat-shaped bowls, and flattened-globular bowls. Rims usually unmodified. Lip rounded, flat-round, flat.

Geographical range of type: Most of peninsular Florida. Seems to center on St. Johns drainage.

Chronological position of type: In the central coastal and Manatee regions of the Gulf Coast it is most abundant during Weeden Island II but probably appears first in Weeden Island I. It is at least this early, if not earlier, on the St. Johns. On the Gulf Coast it continues into Englewood and Safety Harbor Periods.

Bibliography: Goggin (1949, 1944a); Willey (n.d.).