PRELIMINARY REPORT ON PEAT. 
211 
izontal intergradation is found wherever a swamp or marsh is bor¬ 
dered by a hammock or a wooded slope. Peat can also be more or 
less completely transformed into humus by taking it out of the water 
(or draining the water away from it) and stirring, pulverizing, 
composting or cultivating it so as to aerate it thoroughly, until 
finally—after a few years perhaps—enough of the carbon oxidizes 
away, and the acids disappear, for it to be called humus. 
CONDITIONS NECESSARY FOR PEAT FORMATION. 
True peat requires for its formation either a permanent body 
of water or a soil which is saturated with water most of the time, 
especially in warm weather. The water must not he too deep— 
for very few plants are able to grow in deep water—or too much 
agitated by currents, waves or tides, it must not fluctuate in level 
much, and it must not contain too much salt, mud, or other min¬ 
eral substances. 
The most familiar example of permanent water is the ocean; 
but in its deeper parts there is no vegetation except a few micro¬ 
scopic forms, and on all unprotected shores the waves effectually 
prevent the accumulation of peat. Extensive marshes form in 
sheltered bays, lagoons, etc., connected with the ocean, but salt 
marsh peat, for various reasons, one of which is the large amount 
of sediment constantly brought down by rivers, generally contains 
too much mineral matter to be of much value. 
Permanent water is also furnished by most rivers, but many of 
these are too swift or too muddy, or vary too much in level, for 
the formation of good peat. Conditions are somewhat better 
in the estuaries at the mouths of rivers—especially those rivers 
which are not muddy—near enough to the sea to have little current 
and to be little affected by floods and droughts, and far enough 
from it to have hardly any tide or salt water. 
Large lakes are often too deep in the middle, and their margins 
too much disturbed by waves, like the ocean; and shallow ponds 
usually dry up at some season of the year and allow the vegetable 
debris which may accumulate in them in the wet season to oxidize ; 
but between these extremes is the happy mean. Small lakes, or 
shallow bays or coves of larger ones; permanent ponds, and shaded 
springy places, such as the swamps at the heads of streams, offer 
some of the best conditions for peat. 
It goes without saying that peat formation also demands certain 
climatic conditions. The climate must of course not be so cold 
that no vegetation will grow, or so dry that there are no per- 
