190 
FLORIDA STATE GEOROGICAE SURVEY. 
prairie form the western boundary of the main body of the Everglades 
from Lostmans River to Caloosahatchee River. 
The differences of elevation are slight, the islands are rarely more 
than two feet above high water level, and the slopes are . so gentle as 
to be perceived only through the movement of the water or by levelling. 
The general slope south, in spite of the water seen everywhere in the 
rainy season, is not uniform. There are low, irregular rises to be 
measured by inches that serve to diversify the distribution of water and 
sedge-covered peat in the dry months of the year. There are also 
sloughs, narrow, winding strips of open water through the sedge, some 
of which extend for miles. Often it is not possible to detect a persistent 
current in these passages, which, for the most part, seem to have a 
north and south direction along the west side of the Everglades and a 
north-northwest and south-southeast direction toward the eastern side. 
The water brought down by Kissimmee River escapes from Take 
Okeechobee by the canal connecting with the Caloosahatchee and 
through the saw-grass. The short streams around the southern edge of 
the Lake shown on most maps of Florida do not flow into the Lake, but 
from it. They close up within a few miles and the thick growth of 
saw-grass makes the movement of water in any given direction very 
slow. Some of the water entering the Lake reaches the Gulf and some 
the Atlantic, the water moving as a mass slowly southward. The Lake 
is said to overflow into the Everglades along its whole southern border, 
when its waters rise to about 22 feet above mean sea level. 
As evidence of the flatness of the Everglades, residents of the east 
coast state that when the canal leading from the Lake was dammed 
at Lake Hicpochee some five years ago, thereby raising the level of 
the water above the dam 3 feet, more water came down the east coast 
rivers as far south as New River, and the marginal prairies were under 
water so late in the fall as to hinder seriously the growing of vegetables. 
Whether the dam caused all the damage complained of is doubtful. 
Elevation of the Everglades:—Since Lake Okeechobee overflows 
to the south and the waters escaping from it may reach either the 
Atlantic or the Gulf, the elevation of its surface is in a way a measure 
of the elevation of the Everglades. Various determinations of its level 
have been made by government engineers and surveyors. An elevation 
of 20.4 feet was found by a party of engineers in April, 1901, but an 
even lower level 19.8 feet is reported to have been found in March, 1908. 
High water levels, that have been published by the United States 
Engineer’s office, are 22.4 feet in 1886, and 23.4 feet in 1878. Com¬ 
paratively few determinations of elevation at points along the edges of 
the ’Glades have been reported. Some determinations along the eastern 
margin are: West of Lantana, 18 feet; west of Hillsboro Inlet, 14 
feet; west of Fort Lauderdale, 17 feet; at the pool at the head of 
