Key Biscayne S Base Reset
Posted by: BrewSleuth
N 25° 39.970 W 080° 09.384
17R E 584664 N 2838984
1855 U.S. Coast Survey Base Marker
Waymark Code: WM9ZAP
Location: Florida, United States
Date Posted: 10/21/2010
Views: 6
A triangulation survey was conducted by the U.S. Coast Survey with men detailed from the U.S. Army and U.S. Navy. Alexander Dallas Bache, Superintendent of the U.S. Coast Survey, went to Key Biscayne in 1855 to take personal charge of the survey. The survey eventually included Key Biscayne, Biscayne Bay, the Florida Keys from south of Key Biscayne to the Marquesas Keys, and Florida Bay from the Keys to Cape Sable.
When the south base marker for Key Biscayne was set in 1855 it was located on land 300 feet south of the lighthouse, but by 1883, it had disappeared into the sea as the shoreline eroded. It does appear however in a survey as late as 1913 at the low tide line. Subsequent tides, storms, and hurricanes washed away much of the land south of the lighthouse, and the marker was submerged by the sea and eventually covered with sand. In 1988, local professional land surveyors located this marker in 12 feet of water and engaged the U.S. Air Force 301st Aerospace Rescue and Recovery Squadron to salvage it. It was recovered intact offshore and brought to high ground. The men of this time thus helped to preserve the remains of another generation's struggle for excellence in measuring and mapping the earth. The monument was reset as described below.
The station mark is a finely dressed granite monument 16 inches square and 3 feet high with a pyramidal top projecting the 3 feet above a stepped concrete base 4 inches above the ground. The vertical faces of the monument are as follows: North face - Base No. 7 S, East face - U.S. Coast Survey, South face - A.D. Bache Supt., West face - 1855.
Though historic documentation confirms the monument was recovered intact, the original base is described as a granite block 3 feet square and 2 feet thick with a 3/4 inch copper plug in it marked by a cross. The granite base appears not to be reset and replaced by a concrete base. The monument now rests about 20 feet from the seawall.
(above information taken from my own site inspection and Joan Gill Blank's book, Key Biscayne, 1996)
Monumentation Type: Dressed stone
Monument Category: other (not included below)
Monument Category (if other): U.S. Coast Survey
Accessible to general public: yes
Historical significance: First survey of the area for navigational purposes in 1855
County: Dade County
Monumentation Type (if other): Not listed
Explain Non-Public access: Not listed
Monument Website: Not listed
USGS Quad: Not listed
NGS PID: Not listed
Other Coordinates: Not Listed
Other Coordinates details: Not listed
Approximate date of monument: Not listed
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Visit Instructions:
1. A closeup photo of the monument is required.
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2. A 'distant' photo including the monument in the view is highly recommended. Include the compass direction you faced when you took the picture.