SECOND ANNUAL, REPORT—GENERAL GEOLOGIC HISTORY. 
173 
century. The evidence shows that a small pond which was formerly 
overflowed at high tide is now entirely drained and is not invaded by 
the sea except at high tide and after a strong on-shore wind has been 
blowing for at least two days. In 1902, the ordinary high tide was 
reported to fall 300 yards short of reaching the pond, in spite of the 
fact that the connection with the sea was less obstructed than formerly. 
This change which is estimated at from one to one and a half feet 
since the “fifties” is thought to indicate an emergence of the land at 
the rate of two to three feet per century. 
Considering the two cases described above, there are found to be 
two opposite movements represented within a short distance of each 
other. At Apalachicola the observations cover about twenty years 
prior to 1854 and at St. Marks they cover the last half of the century. 
Granting that observations recorded should be given full credence, 
there still remains a question as to whether there was a change in the 
direction of movement about the middle of the century, or whether 
there are two opposite movements on the same coast. 
The only record of recent movements on the east coast is contained 
in a brief note by Lewis. 1 This writer reports the submergence of 
stumps of cedar trees at St. Augustine. The amount of the move¬ 
ment is not recorded. 
The recent geologic and topographic changes of importance con¬ 
sist of the deposition of coquina, sand, marl, peat and muck, and the 
formation of sand dunes and ridges. There is a rapid deposition of 
sand and coquina taking place along both the Atlantic and Gulf coasts 
and more or less marl and partially decomposed organic matter, in the 
form of peat and muck, in the marshes and lagoons. The formation 
of dunes and ridges of sand is especially active along the east coast 
as far south as Hobe Sound, and a similar action, on a much smaller 
scale, is taking place in the interior of the State. Solution and the 
consequent formation of underground channels, sink holes and natural 
bridges doubtless began with the emergence of the calcareous rocks 
and it is still going on. The effects of solution are shown by the 
emergence of water bearing mineral matter in solution and by the 
occasional subsidence of small areas. 
1 Lewis, E. Evidence of a probable modern change of level on the coast 
of Florida, Am. Jour. Sci., 2d ser., vol. 41, 1866, p. 406- 
