212 FLORIDA GEOLOGICAL SURVEY-I3TH ANNUAL REPORT

 In dry weather fire originating in the surrounding pine forests occasionally sweeps through a cypress pond, but the pond cypressunlike its better-known relative in the river and lake swamps-has such thick bark that it is not usually materially injured thereby. The only economic importance of this vegetation at present seems to lie in the value of the cypress for poles, cross-ties, shingles, etc,
 Bavs. The same sort of depressions that ordinarily contain cypress pond vegetation often have instead a dense growth of shrubs and small trees, mostly evergreen. This sort of growth, with or without a few scattered taller trees, in shallow stagnant or slowflowing water, is called a bay in Georgia and Florida, probably on account of the usual presence in it of bay trees (Magnolia glaiica. Persca pitbcscens, or Gordonia Lasianth us). Whether a given depression sto be occupied by cypress pond or bay vegetation, or no trees at all, seems to be determined chiefly by the depth and seasonal fluctuation of the water, as suggested in the Sixth Annual Report (page 203) ; bays being in those whose water fluctuates least.
 The bays in the lower parts of Middle and West Florida were described in the Third Annual Report, pp. 264-265. In central Florida they are less common, but occur in a number of places in the flatwoods and the lake region. A variation with fewer shrubs and a great deal of slash pine was described under the head of slash pine bogs on pages 256-257 of the same publication. Some of the peat prairies have dense clumps of bay-like vegetation dotting their surfaces, as indicated on a preceding page, and on pages 274-275 of the report just cited.
 Typical bays are practically exempt from fire, but slash pine bogs are burned occasionally. The bays are of very little economic importance. except that some of the plants in them yield honey.
 Non-alluvial suainps. Wherever water that has percolated through the surface sands without coming in contact with any calcareous strata seeps out on the surface in sufficient quantity throughout the year there is likely to be a dense shady swamp containing bay trees, maple, black gum, bamboo vines, etc. Such swamps (described in the 3rd Annual Report, pp. 258-260) differ from the bays just described chiefly in having a greater flow of water and more trees and fewer bushes. They are widely distributed through the coastal plain from Long Island to eastern Louisiana, but not very common in peninsular Florida, where they are