88 



FLORIDA GEOLOGICAL SURVEY I3TH ANNUAL REPORT 



The portion northwest of the Suwannee River was described in the 

 6th Annual Report, pages 302-309, and a few of the vegetation 

 types in Sumter County in the 7th. 



Fig. 6. Hydro-electric power-house with 20-foot dam (built in 1911), on 

 Withlacoochee River about 10 miles below Dunellon. March 4, 19 15. 



Topography mid Geology. The region is mostly flat and less 

 than 75 feet above sea-level, and is underlaid throughout with a 

 hard limestone (Oligocene), that is exposed in innumerable boulder- 

 like or larger outcrops.* There are occasional irregular low sandy 

 ridges, scarcely distinguishable from parts of region No. 4, where 

 the depth to the rock is unknown. The coast is unlike any other oi 

 equal extent in the world, as far as known, in being bordered by 

 marshes instead of sandy beaches; the reason being apparently that 

 the slope of the ocean bottom here is so gentle as to practically eli- 

 minate wave-action on the shore, just as if there was a barrier beach 

 a few miles off shore. Stern-wheel steamers from the Suwannee 

 Ri^'er ply the open Gulf from the mouth of that river to Cedar 

 Keys. The same limestone rock th'at characterizes the region is said 

 to crop out on the bottom of the Gulf some distance out. Some of 

 the rivers have rocky shoals a few miles from their mouths, and 

 the one on the ^^'ithlacoochee is utilized for power purposes. 



*See fig. 5. The soil survey of Hernando County shows one solid area 

 of rock outcrop in the eastern end of the county covering about half a square- 

 mile. 



