Antiquarians of the nineteenth century referred to the largest monumental
constructions in eastern North America as pyramids, but this usage faded
among archaeologists by the mid-twentieth century. Pauketat (2007) has
reintroduced the term pyramid to describe the larger, Mississippian-period
(A.D. 1050 to 1550) mounds of the interior of the continent, recognizing
recent studies that demonstrate the complexity of their construction. Such
recognition is lacking for earlier mounds and for those constructed of
shell. We describe the recent identification of stepped pyramids of shell
from the Roberts Island Complex, located on the central Gulf Coast of
Florida and dating to the terminal Late Woodland period, A.D. 800 to 1050,
thus recognizing the sophistication of monument construction in an earlier
time frame, using a different construction material, and taking an
alternative form.