REVIEW OF THE GEOLOGY OF FLORIDA I 3 I 
Interpretation: The limestone at the surface is the Key Largo 
Coraline limestone, Pleistocene. The sands containing phos¬ 
phate pebble and some clay and extending in this well to a depth of 
585 feet are referred to the Miocene. The limestones below 589 
feet, according to Cushman, contain foraminifera indicating the 
Oligocene, and at and below 1,248 feet the Comanchean. The 
Eocene may be represented, although no identifiable foraminifera 
were obtained from the Eocene. The Pliocene likewise may be 
present, although not indicated by fossils. 
ASYMMETRY OF THE FLORIDIAN PLATEAU. 
The actual position and extent of this plateau, as has been 
shown by Smith, Vaughan, and others,* is strikingly different to 
that which appears from the inspection of an ordinary map of the 
land areas. The ioo-fathom contour may be taken as the approx¬ 
imate margin of the plateau, since the slope to this line is for the 
most part gradual while beyond this contour the slope is rapid, and 
in places, especially toward the south end of the peninsula, is 
abrupt. Taking this ioo-fathom contour as the margin it will be 
found that scarcely one-half of the plateau is above water, and that 
the greater part of that which is above water lies to the east of the 
north-south axis. With regard to elevation the plateau is there¬ 
fore asymmetrical, the eastern half being higher, mostly above sea 
level, than the western half which is almost wholly submerged. 
This lack of symmetry is apparently due in particular to a tilting 
or warping of the peninsula toward the west, by which the coast 
of West Florida has been depressed as far south as Hernando 
County, while the east coast including all of the southern tip of the 
peninsula, has been slightly elevated. 
f *Smith, Eugene A. On the Geology of Florida. Am. Jour. Sci. (3) 
Yol 21, pp. 292-309. 1881. * Vaughan, T. Wayland. A Contribution to the 
Geologic History of the Fldridiari Plateau, Carnegie Institution Of Washing¬ 
ton, Pub. No. 133, 1910. 
