US Army Corps of Engineers
Jacksonville District Website

In the early part of World War II the United States leased 2,560 acres of unimproved land for use as a U.S. Army Air Corps aerial practice bomb range associated with the Sarasota Army Air Field (AAF).  The bull's-eye target consisted of three concentric circles with an outside hexagonal warning line constructed of an unknown white material.  The property was declared surplus in 1946 and the leases were terminated in June 1946 and the land was returned to the owners. 

 

RECOGNIZE - The object you found could be dangerous.
RETREAT - Leave the area without touching or moving the object.
REPORT - Call 911 immediately.