The Mill Cove Complex: A Center on the Periphery

Dr. Keith Ashley of UNF discusses excavations at Grant and Shields Mounds, along the St. Johns River. This talk, presented at the Timucuan Science Symposium on January 25, 2013, explores the trade relationship between this site and Cahokia, the massive Mississippian Period site outside of St. Louis.


  1. The sites studied date from about 900-1200AD.  Along with Mount Royal, this area (called the Mill Cove Complex) interacted extensively with Cahokia, a major Mississippian cultural center.  Both of these northeast Florida site reveal presence of exotic metals, minerals, and stones.

    As seen below, Mississippian cultures traced and radiated out from the Mississippi River and throughout the Southeast.  The red line through north Florida and Southeast Georgia indicate a break from Mississippian cultures, perhaps rendering trade among these groups even more significant.
  2. The Mill Cove Complex dominates the landscape at the mouth of the St. Johns River.  Located on old dune fields, it is the largest St. Johns Period site in northeast Florida.  The site consists of habitation, refuges, ordinary middens, ritual middens, and sand burial mounds.  Sacred areas were built on naturally occurring high spots in the landscape.
  3. The St. Johns II people who occupied this site had easy access to life-sustaining resources: fish, shellfish, reptiles, wild plants and animals.  They were not isolated from events affecting the southeast as a whole; rather they were part of far-flung networks.  These networks don't become clear in the archaeological record until materials dating to about 900AD.  At that time, both Grant and Shields Mounds exhibit heavy interaction with distant populations.

    Grant and Shields, both mortuary mounds, constitute the two most conspicuous aspects of the Complex.  Located 650-700m apart, they are connected through use.  Much of what is known about these mounds derives from excavations undertaken by CB Moore.
  4. CB Moore, a wealthy socialite of the late 19th century, used his inheritance to buy a steamboat and come to Florida in the 1890s to excavate sites. 

    When he reached Grant Mound, it was 24 feet high, but already eroding.  Unfortunately, development in the area over the past several decades hasn't helped that issue:
  5. Both mounds are accumulated cemeteries that were reconfigured as time passed by the additions of human remains.  As such, they serve several functions: they store social memory, provide opportunities to reaffirm ties to land and ancestors, and tie together the living & dead.  These people weren't putting remains in the ground; rather, they built standing, visible reminders of their ancestors.

    During Moore's excavations in 1895, he uncovered a multitude of exotic goods; these included copper masks of Long-Nosed Gods derived from Cahokia, biconical earspools made of copper-covered wood, and spatulate celts.  The copper itself is nonlocal--its trace elements indicated it came from the Appalachian Mountains in the Lake Superior region.  Likely the copper was sent as banged-out, flat sheets.  Upon receiving them, people could adapt them as necessary to create or adorn objects.  Moore found other exotic materials as well, including mica derived from the Appalachian Mountains and galena from the Ozark Mountains.
  6. As UNF plans ongoing excavations at the Mill Cove Complex, Ashley examines discrepancies between CB Moore's 1895 map of the site and a modern LiDAR map (Light Detection and Ranging data).  We don't know whether or how much Moore's map may have been flawed; nor do we know how much the contour of the land itself has changed.

    Whereas Moore's excavations occurred primarily on the north end of the site, UNF's focus is to the south.
  7. Because the site has seen extensive development over the years, UNF undertook unusual means to gain access: they went door-to-door and asked permission to dig.  Dr. Ashley commends the cooperating landowners as great collaborators and stewards of the site.

    Since 1999, excavations have focused on Kinzey's Knoll, a midden located in someone's front yard, which would have been in the shadow of Shields Mound.
  8. When they began excavation, they couldn't get a probe through the ground, it was so solid with shell--indicating heavy occupation.  Over the past decade and a half they've been back several times to put in excavation units, including one in January 2013. 
  9. The shell deposit has proven to be solid, and 80cm thick.  But in addition to shell, they're finding materials more consistent with a mortuary mound than a midden: lots of ceramics (maybe made especially for a particular event), engraved bone pins, dolphin teeth, a drilled shark tooth, and quartz crystal. 

    Though northeast Florida has a dearth of native stone to use for projectile points, several nonlocal points have been found.  Among these are points from other parts of Florida, like Pinellas points, but also some unexpected specimens.  Some Citrus and Santa Fe points have been found; these predate the Mill Cove Complex by 3-4000 years, maybe indicating an appropriation of the past.  Perhaps more stunning is the presence of Cahokia points--of which three have now been found (Dr. Ashley points out two such points below).
  10. As in Moore's excavations, other exotic items are turning up at Kinzey's Knoll including copper--often warped from being worked, and greenstone with red ochre.  Red ochre was ground into a powder and mixed with white & yellow sand to create pinkish layers in the mounds.  Evidence of work done on these exotic items is present too, in the form of deer antler and sandstone used to modify materials.

    Excavations continue to turn up materials that predate the site itself--bannerstones, stone pipes, and other artifacts from the Archaic.  This trend indicates that the St. Johns II people may have been digging up older mounds to deliberately draw on and connect to the distant past.
  11. Some human bone has been found at Kinzey's Knoll, consistent with processing human remains for bundle burials.  In this process, bodies would be stored and defleshed, then disarticulated and bundled before being placed in a mound. 

    Aside from exceptional and ritual-related finds, UNF is finding ordinary materials too--albeit in extraordinary quantity.  Like the shell, Kinzey's Knoll has yielded massive amounts of animal bone; more bone, says Dr. Ashley, than any known site on the Atlantic Coast.
  12. Ashley turns back to exotic goods in closing: the exceptional quality of the Mill Cove Complex is not simply in the presence of these goods, but their abundance.  Typically, when items are traded, a gradual decrease in frequency coincides with distance from the source.  In other words, while one might expect to see many Cahokia points (for example) in communities surrounding Cahokia, we would expect to see fewer as we move away from that area.  And that largely holds true with these exotic goods, until reaching the Mill Cove Complex--where materials from distant sources abound.

    To Dr. Ashley, this indicates a deliberate effort.  He interprets this phenomenon as intentional, serving the purposes of direct diplomatic relations with Macon area mounds and Cahokia.  This theory has been bolstered as the University of Missouri analyzes pottery samples to test clay origins.  So far, they've found that some of the ceramics derive from the Macon area, and others are local to the Jacksonville area.  It's likely that women were marrying between those groups and carrying their ceramic technology (knowledge) with them. 

    For more about these sites and the relationship between prehistoric societies in Florida and Mississippian cultures, find the new book Dr. Ashley coauthored, "Late Prehistoric Florida: Archaeology at the Edge of the Mississippian World".