SOME FLORIDA LAKES AND LAKE BASINS.

Miccosukee Basin has a total area of about 5,oo00o acres. In its northern part the basin is bordered by sharply defined bluffs, which rise from 50 to 75 or 100oo feet above the lake bottom. Farther south these bluffs fall back and give place to a gradual rise of elevation from the lake border. At the south end bluffs are lacking. A drain known as Miccosukee drain enters irom the east side. This drain consists of a low, swampy area from one-fourth to three-fourths mile in width. This swamp land supports a thick growth of hardwood trees.
When full, Miccosukee Basin is covered with water to a depth of from 2 to 5 feet. Toward the south end around the border of the lake grass and button bushes project above the water even when the lake is full.
The sink of Lake Miccosukee is located near the north-west corner (see Fig. 4). The sink is bordered by a bluff having an elevation of from 75 to Ioo feet. Landslides along the border of the sink show recent enlargements of the basin. Numerous sinks occur along the border of the lake at this locality, showing enlargement of the lake basin through subsidence. The greatest depth of water found in the sink when examined September 7, 1909, was 38 feet. A .channel leads back from this sink across the prairie in a south-easterly direction. This channel has cut to a depth of from twenty to twenty-five feet. Followed back from the sink the channel is of gradually reduced depth finally at a distance of about two miles merging into the general level of the lake bottom. When examined September 8, 1909, this stream was carrying water into the sink at a rate estimated to be 2oo gallons per minute. Notwithstanding the inflow from the stream the water in the sink was being gradually lowered. Heavy rains oc-curred in this vicinity on September 21, 1909, and this stream when seen two days later was carrying approximately 7,00ooo gallons of water per minute. At this time the sink was being rapidly filled, having filled several feet during the two preceding days. From these observations it appears that the opening at the bottom of this sink permits the escape of water at a rate in excess of 2oo gallons per minute, but much less than 7,oo000 gallons per minute. From the behavior of the sink it is probable that not more than I,ooo gallons of water are escaping per minute, and the rate of escape may be much less.
The principal escape of water from Lake Miccosukee when the lake is full is through a drain which leads out from the south end of the lake and enters a sink about two and one-fourth miles from the south end of the lake. This sink is formed in a light colored limestone of Upper Oligocene age, probably representing the Chat-

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