18 FLORIDA GEOLOGICAL SURVEY-I3TH ANNUAL REPORT

 If any showings of oil have been found in the wells so far drilled they were small, and .the great thickness of limestone underlying the surface formations in Florida does not encourage an expectation that oil will be found there in commercial quantities, for oil is usually associated with thick deposits of shale, in which it presumably originated. The evidence available at the present moment does not seem to justify sanguine hope.s of developing an important oil field in this State.

 STRUCTURE OF THE ROCK BEDS,

 The dominant structural feature of eastern Florida is an anticlinal fold, or arch, which.trends south-southeastward and forms the axis of the peninsula. The. axis of this arch passes near Live Oak, 10 to 20 miles west of Gainesville, and an equal distance west of Ocala, and is the southern cdintinuation of the broad anticlinal area of south-central Georgia. Along this anticline there are two high areas. The highest part of one, called the Ocala uplift, appears to be in eastern Levy County: that of the othei- is near Live Oak. The Ocala uplift is the larger and the higher. On this uplift the Ocala limestone is found 120 feet above sea level. From that elevation it dips toward the east to a depth of 200 feet below sea level at St. Augustine and 5oo feet below sea level at Jacksonville.
 The Ocala uplift is separated from the uplift near Live Oak by a low area, or saddle, which runs parallel to the axis of the anticline. to a point near Santa Fe River, in southern Columbia County.
 From that point the beds appear to rise gently to form a domeshaped fold near Live Oak. The Ocala limestone is found at Suwannee, Ellaville, Dowling Park, and Luraville, on Suwannee River, at elevations ranging from 35 to 45 feet above sea level, whereas the Chattahoochee limestone, which overlies it, is 120 feet above sea level at Live Oak. As the Chattahoochee here has an estimated thickness of 30 to 40 feet, the Ocala is probably 40 feet higher at Live Oak than at any of the exposures on the Suwannee or at Bass, a fact which suggests the inference that a dome-like uplift centers at Live Oak. This inference is strengthened by the fact that the top of the Chattahoochee limestone stands at an ele-