60 - BOTANICAL GAZETTE [AUGUST 
arrangement and naming of the different types of peat are merely 
matters of practice in field work. 
In this paper it is not the intention to furnish the numerous 
details necessary to a knowledge of the different types of peat 
material, nor is it necessary to review from a voluminous European 
literature all the widely scattered observations on types of peat 
and their variations. So far as observations indicate, variations 
of stratigraphic units represent but a temporary condition. The 
structural development of a peat deposit is characterized by the 
regular occurrence of several types of peat material in many 
different forms and phases, such as differences in the growth and 
evolution of vegetation units. These phases are connected by 
more or less constant field relations. Unquestionably many so- 
called ecological stages represent merely fragments in the develop- 
ment of a peat deposit, reactions of one plant population upon 
another. On the other hand, well distinguished types of peat 
material will not only keep their position, but will receive a much 
more nearly complete and sharper definition than they have at 
present. It is for these reasons that only major divisions of plant 
remains are distinguished in the following discussion. They have 
been adopted also wherever the differences of information are 
sufficient to occasion difficulty in applying a uniform classification 
of types of peat. The list has been summarized (5), and has been 
utilized with the addition of two new marsh types of peat found 
in Florida and California respectively, to facilitate reference be- 
tween the cross-sections of peat deposits and the text. 
The conventional signs represented in the graphic illustrations 
of the profile sections described in large part are adjusted to the 
standard of European workers and the requirements of cartography. 
The departures which arise (partially from thé inaptness of the 
material as a type of peat) have been stated in the legend, and 
in connection with each layer described in the text. Beds or 
strata which are not sharply defined in a deposit may be recognized 
by the dotted boundary lines. 
It is to the interest of a group of scientific and industrial workers 
that coordinated efforts should be brought to the solution of 
peat-land problems. ‘To those who desire general field information 
