294 FLORIDA GEOLOGICAL SURVEY THIRD ANNUAL REPORT.
FOSSIL PEAT.
Peat has doubtless been forming in some parts of the world almost ever since vegetable life began, a period presumably of many millions of years. The peat of the Carboniferous period is now our anthracite and bituminous coal, a material without which the stupendous industrial developments of the past hundred years would have been impossible. Smaller amounts of true coal are also founi in Triassic and Cretaceous strata. Next in importance of the prehistoric peat deposits is the lignite of the Tertiary period, a sort of imperfect coal whch is used for fuel, etc., in many parts of the world where it is more easily obtained than real coal. All the rocks in Florida which have been reached by artesian borings are of later formations than the so-called Lignitic, and all the fossil or buried peat which is known in this State, with one or two unimportant or little-understood exceptions, is comparatively recent, probably not older than Pliocene.
Fig. 29.-Ledge of black hardpan on shore of bay about a mile wvest
of Apalachicola, Franklin County. April 24, 9I0.
As long ago as 1827 Col. J. L. Williams noted the occurrence of a stratum of peat-like substance, containing cypress and cedar stumps, a short distance below the surface sands on the peninsula between Pensacola Bay and Santa Rosa Sound.* Well-drillers in various parts of Florida and elsewhere in the coastal plain frequently report finding logs buried at various depths, which prob* See Smith, Tenth Census U. S. 6:223. 1884.