122 FLORIDA GEOLOGICAL SURVEY-I3TH ANNUAL REPORT

outlet. They are, comparatively deep, and never go dry, though they may fluctuate a few feet from one year to another with the amount of rainfall. Many of the smaller ones at higher elevations beai evidence, in the shape of young pine trees around their shores, 01 being a little lower now than they were a generation ago. (See fig. 22). This may be due to a permanent lowering of the groundwater level by numerous artesian wells with outlets at lower levels. Unlike those in the lime-sink region and hammock belts, none of tne lakes are known to have any subterranean outlets.
 Streams are not very numerous, for most of the rainfall sinks almost immediately into the deep sand which covers the uplands. They are nearly all sluggish and coffee-coloreq. The St. John's ana Ocklawaha Rivers are navigable for small steamboats all the way through the lake region, and being bordered by tropical-looking vegetation, are favorite scenic highways.

















 Fig. 20. Lake Alfred, a clear lake in the highlands of Polk County, showing a fringe of maiden cane and bonnets a few yards off the sandy shore and parallel with it. May 18, 1910.
 Soils. The soil of the uplands is mostly a slightly loamy sand several feet deep, usually creamy or light buff in color, but varying to yellowish, brownish, and ashy gray, the last being found chiefly a few miles south of Lakeland, near the edge of the pebble phosphate country. There is probably more pure white sand (scrub) in this region than in any other, but there are no data yet for making