GEOGRAPHY OF CENTRAL FLORIDA 169

wide. They nearly all originate in and are bordered by swamps, and are decidedly'coffee-colored.
 The outlets of the large springs, varying in size from creeks to small rivers, are commonly called runs. They are clear and bluish like the springs, but usually do not flow more than a few miles before they lose themselves in some larger coffee-colored stream or in the ocean. Helena Run, in Lake County, is said to be transparent when it flows eastward from Bugg Spring into Lake Harris, and coffee-colored when it flows westward from the lake toward the Withlacoochee River.*
 The larger rivers are all coffee-colored in their natural state, there being no naturally muddy water in peninsular Florida; bilit a few like the Alafia and parts of the Withlacoochee are kept turbid most of the time by washings. from the phosphate mines in their vicinity. The rivers are as a rule sluggish, because the highlands of the peninsula are so narrow that streams originating in them get down into the flatwoods before becoming large enough to be called rivers.
 There. are, however, a .few places where ledges of rock form rapids, particularly in the Gulf hammock region within a few miles of the coast. One such place on the Withlacoochee, about ten miles from its mouth, and the same distance below Dunnellon, has been made the site of a hydro-electric plant (fig. 6), with a 20-foo dam, furnishing power to Dunnellon, Brooksville, several phosphate mines, and even an orange packing house in Sumter County. There is another such plant on the Hillsborough River a few miles from its mouth (in what is regarded as a part of'the lime-sink region). which however is said to be used only for emergencies, as it cannot furnish enough power for the whole city of Tampa. There is said to be a spring near Sumterville which furnishes power for a mill.t

 *See 3rd Ann. Rep., p. 281.
 tAccording to U. S. Geol. Surv. Water Supply Paper 319, p. 406. There has been some talk of damming up other springs in central Florida for power purposes, but just why a spring should be selected for that purpose, rather than the same stream farther down where it is larger, is not clear, unless it is merely a manifestation of a mania some people have for destroying or defacing ob,.iects of natural beauty. Some attempts of this kind in West Florida are said. to have had the unexpected result of merely forcing the water to find a new outlet through the cavernous limestone.