126 FLORIDA GEOLOGICAL SURVEY SIXTH ANNUAL REPORT. 



red clay hills characteristic of this part of the State. These hills 

 rise to an elevation of from 50 to 75 feet above the level of the 

 lake. 



2"]. — Sketch map showing the location of lakes lamonia, Jackson, 

 Lafayette and Miccosukee in Leon and Jefferson Counties. 



The sink through which the water escapes from this lake is 

 found on the north border. When visited May 7, 19 10, the sink was 

 practically dry, having only a small amount of water in the bottom. 

 Limestone rock, probably of Upper Oligocene age, is exposed near 

 the bottom of the sink, the water escaping through or under these 

 rocks. Above the limestone partly decayed sandy clays occur. 

 1 hese contain few fossils, although oyster shells were found in 

 al.^undance at one locality. The total depth of the sink below the 

 general level of the lake is not less than 50 feet. The sink occurs, 

 as is usual in this type of lake, facing an abrupt bluff 30 feet or 

 more in height. A considerable number of sinks occur around the 

 border of the lake especially in the vicinity of the one large sink 

 Vv'hich receives the drainage of the lake. The formation of these 

 sinks is doubtless due, as previously stated, to the fact that the water 

 entering the drainage sink spreads laterally in the underlying lime- 

 stone and dissolves the rock rapidly. The result is the formation by 

 subsidence of numerous sinks adjacent to the drainage sink. The 

 presjence of these sinks also indicates the manner of enlargement of 

 the lake basin, and indicates in each case the direction of most 

 rapid enlargement at the present time. At other times the enlarge- 

 n^ent by solution and subsidence mav have been most active in some 

 other locality or direction or part of the lake basin. 



