290 
FLORIDA GEOLOGICAL SURVEY—THIRD ANNUAL REPORT. 
TREES 
Pinus serotina (.black pine) 
Magnolia glauca (bay) 
Gordonia Lasianthus (bay) 
Persea pubescens (red bay) 
SHRUBS 
Aralia spinosa (prickly ash) (most' Smilax laurifolia (bamboo vine) 
ly near the edge) 
HERBS 
Osmunda cinnamomea (a fern) 
The width of this part of the swamp is about 200 yards, and 
at that distance from the edge the peat is about 8 feet deep. At 
the time of my visit, in January, 1909, the swamp seemed to 
have been burned over within a year or two, which had lowered 
the surface of the peat a few inches, and also allowed blackberry 
briers and a few other weeds to come in. Some parts of it had also 
been ditched and cultivated to some extent. Analyses of peat from 
this locality (No. 8.2) show it to contain only about half as much 
ash and sulphur as that from nearer the river, and its fuel value is 
higher. 
THE “INFUSORIAL EARTH” BOG. 
About 3 miles east of Tavares, on the north side of Lake Dora, 
is a bog covering nearly 100 acres, of the peat prairie type already 
described, which on the surface looks like many other small filled 
lakes in the same region. But it differs from all others that I have 
seen in the composition of the ash of the upper layers of the peat. 
A chunk from near the surface contains so much mineral matter 
that when dry it has a grayish color, instead of the usual black or 
dark brown. This mineral matter has been found to consist 
mostly of the shell of diatoms, and when such peat is burned 
the diatoms remain as a very fine and light white powder, having 
much the appearance of flour. (The uses of this material will be 
mentioned in a subsequent chapter.) , 
A ditch about six feet deep, leading through a low ridge of 
scrub to the eastward, has altered conditions to the extent of keeping 
the average water-level a foot or so below the surface of the peat, 
when it was originally no doubt a little above the surface. 
According to Hon. H. W. Bishop of Eustis, who was formerly 
interested in this property, the ditch was dug about 1896 by a man 
who intended to raise tobacco on the drained peat. In this he was 
