A boatyard in Gale's Point


The Mangonia Boatyard

Excavations and monitoring at 3336 North Flagler Drive uncovered the remains of the floor of one structure, likely one of the boat repairs houses, based on its location and associated rails for hauling boats in and out of Lake Worth. The site was denominated the Mangonia Boatyard. The boatyard structures are depicted in the 1920 Sanborn map. Approximately 12 by 4 meters of the floor as characterized by a wooden structure consisting of wide planks supported by beams, was uncovered 1.70 meters below the fill.  Associated artifacts included iron fasteners, a boiler, and glass bottles. In addition, a crankshaft was found in the fill, and likely fit for the steam engine found in 1972. 

Mound in Palm Beach Island


Mound in Palm Beach Island

The site was characterized as an elevated shell mound that measured about 100 feet north to south and about 50 feet wide, although it was measured about 400 feet north to south and about 100 feet wide based on a 1895 plat map. The mound had an elevation of about 20-30 feet above the sea level. The site was characterized by areas of dense midden containing oyster shell, faunal bone, and prehistoric ceramics. A sand mound also was documented on the western part.

The most intact archaeological deposits occur in the northeast area of the parcel where the new residence will be situated. Most of the recovered prehistoric material consisted of shell refuse and faunal bone. Artifacts include prehistoric ceramics, most being sand-tempered plain. Other artifacts include a shell celt (Busycon), drilled shark teeth, and a socketed bone point. Of particular interest are two unidentified coprolites. The coprolites are of scientific significance because they have preserved materials that could provide important information about diet, disease and DNA. It is likely that the site is at least 1000 years old, but radiocarbon dates are pending. Previous references indicate the existence of a shell mound and human remains associated with the site .

Fossil Deposit in Palm Beach


Fossil Deposit in Palm Beach

In 2017, a Pleistocene fossil deposit was found in an excavated pit in Palm Beach County. The fossil deposit was discovered during a pedestrian survey. Large mineralized mammal bones and tooth fragments were identified. 

The bones are associated with a concreted marl or limestone. The bone bed is about one meter below the surface, and appears associated with a remnant creek and pond that may have been a water source during the late Pleistocene.  

Based on pedestrian survey and spoil inspection, the deposit appears to be relatively dense with fossils of a variety of taxa, including mammoth, horse, and deer. No cultural materials were observed. The fossil bed clearly extends beyond the excavated pit.  

Miami Circle


Miami Circle

The Archaeological and Historical Conservancy played a major role in the discovery and preservation of the Miami Circle, providing an opportunity for archaeologists and archaeological technicians to uncover the Circle, and donating over $40,000 to the project cost. We also directed the analysis of over 143,000 objects that were recovered from the Circle, many now featured at an exhibition at the Historical Museum of Southern Florida in Miami.
The Miami Circle was discovered in September of 1998 during routine archaeological monitoring on a proposed condominium site at the mouth of the Miami River. 

Then Miami-Dade County Historic Preservation Director Robert Carr supervised the excavation of several test units which revealed basins cut in the bedrock, each filled with black dirt midden. Surveyor Ted Riggs recognized that the basins formed an arc, and hypothesized that it might be part of a circle. In September 1998, a 40 foot diameter area was excavated, revealing that the basins formed a circle.
The area within and around the circle was excavated, with the field work being directed by County Archaeologist John Ricisak. While the developer was having permit delays, archaeologists from the Archaeological and Historical Conservancy and dedicated volunteers continued to excavate the site and make important discoveries. Rare stone celts were found as well as animal burials: a sea turtle shell, a dolphin skull, and an articulated shark skeleton, that appear to be offerings. Radiocarbon dates suggest the shark dated to around 1600 A.D. while charcoal found directly on top of the bedrock and in the basins dated to ca. 200 - 300 A.D. 

As the importance and antiquity of the site was being revealed, public attention heightened. A campaign began to save the circle from development. Native Americans visited the site, school children signed petitions, and international media gave it coverage. The campaign culminated with an eminent domain law suit filed by Miami-Dade County. This meant that the government valued the land as a cultural heritage site too much to allow it to be destroyed. The lawsuit was settled and the circle was acquired jointly by Miami-Dade County and the State of Florida. The park is now managed by the Historical Museum of Southern Florida. 

Summary of Field Work done at the Miami Circle

  • The site was discovered and excavated by archaeologists with the Miami-Dade County Historic Preservation Division. Archaeologist Robert Carr supervised the project and former Country Archaeologist John Ricisak directed the field work. Archaeologists from AHC and volunteers from the community helped excavate the circle and some small areas immediately around it.
  • State of Florida archaeologist, Dr. Ryan Wheeler, tested other areas of the two acre parcel and verified the age and authenticity of the site. This work was important to the County in their decision to proceed with an Eminent Domain lawsuit and purchase of the site.
  • Dr. Dolph Widmer of the University of Houston conducted a field school (training school for archaeology students) there, examining an area closer to the mouth of the river, under the auspices of AHC.
  • Archaeologists from the Archaeological and Historical Conservancy catalogued the mass of artifacts and information gathered from the Miami Circle using a grant provided by the State of Florida's Division of Historic Resources, jointly given to the Conservancy and the Historical Museum of Southern Florida. The collection now reposes at the museum.
  • During 2004 the staff of Mnemotrix conducted a ground penetrating radar (GPR) survey as a reverse ground truth study to catalogue the excavated features in a 3D GPR visualization.
  • In 2007 the Miami Circle was listed in the National Register of Historic Places.
  • In 2009 the site was designated a National Landmark.


The current interpretation of the circle by most Florida archaeologists is that it represents the footprint of a structure. Due to its careful construction and size (38 feet in diameter), it probably had a sacred and/or public function. The remains of sacrificed animals suggest ritual ceremonialism at the site. A more detailed discussion of the site can be found in the 2000, 2004, and 2006 issues of The Florida Anthropologist (Volume 53 No. 4, Volume 57 No. 1-2, and Volume 59 No. 3-4).