In the early 1800s, ship captains trying to find the entrance to the
St Marks River in N. FL would be guided by a plume of smoke of unknown
origin that seemed to come from deep in the swamp somewhere NE of the
river entrance. This plume was seen over many years and was sometimes
said to originate from something volcanic. In the early 1800s until
about 1869, it could often be seen from rooftops of buildings on the
tall hills of Tallahassee by looking way to the SE. It could not be
reached due to its being deep in the impenetrable swamps. One party
tried to approach by boat and got about a mile NE of "Grey Mare Rock"
but could not get closer due to shallow water but they estimated they
were still 10 miles from it. It went away by the late 1800s
supposedly coincident with the Charleston Earthquake that rang
churchbells in Tallahassee.
In the 1900s, some people said they new of its location and it was a
place of blackened rocks surrounding a hole in the ground. Being a
5th gen N. FL native, I am sorta interested but it was never
volcanic. The approximate bearings given and supposed approximate
locations seem to put it somewhere near the Aucilla Sinks area, a
bizarre area of Karst features where the Aucilla River goes
underground and up again numerous times and is strewn with large
limestone boulders, some of them blackened with fungus and lichens.
This area would look bizarre even to a native familiar with sink
holes.
So, what caused the smoke plume? The best theory seems to be a long
smoldering peat bog although even this sounds odd in such a wet
place. The area was never fully explored until this (1900s) century
when it was logged for cypress and pine and even then they avoided the
most difficult areas such as the Aucilla Sinks area.
I wish I could find some records of actual bearing to it from known
locations but have not found such. After more than a century, I
wonder if evidence of a peat bog fire would still be evident.