1921] DACHNOWSKI—PEAT DEPOSITS 63 
and dryness by means of which decomposition and oxidation are 
accomplished. The layer represents rather the open scattered 
growth of plant populations, such as sedges, reeds, rushes, and 
brown mosses. The “well decomposed” débris as a rule is the 
intermixture of macerated material from aquatic and amphibious 
plants. The presence of diatoms, sponge spicules, shells, silt, and 
windblown material of various kinds usually shows that the chief 
condition for its formation is a higher water level. So long as the 
water table continues at a higher level, the fibrous type of peat 
tends to retain the aquatic admixture; the disappearance of the 
macerated débris would indicate conditions of ground water below 
the surface soil; and an alternating sequence of these layers would 
mark a period of climatic pulsation, of alternating wet and dry 
conditions. In carrying out quantitative determinations on sam- 
ples of “well or partly decomposed” peat materials, the use of 
the colloidal suspension test and the methods of K6nic (15), 
MELIN and Op£EN (22), and KEPPELER (13) are only partly ade- 
quate. The possibility of obtaining erroneous results must be 
checked by a preliminary microscopic examination of the organic 
material, and by a consideration of its position in the profile struc- 
ture of the deposit. 
Some European workers are strongly of the opinion that a 
climatic break in the waning portion of the glacial period is indicated 
by the remains of forests found buried in stratified peat deposits, 
and by the “‘horizon”’ layer between the lower, in part disintegrated, 
and the upper, relatively more recent sphagnum peat of certain 
high moors. The materials are believed to be evidence showing 
there has not been merely a steady amelioration of climate since 
the last ice movement, but rather a fluctuation between periods 
of dry and wet climatic conditions. The dissent from this inter- 
pretation on the part of other investigators does not appear to be 
chiefly a matter of the proper terms to apply to types of peat and 
their variations, These layers of “horizon” peat and of buried 
forest, however, constitute more properly supra-aquatic types of 
plant remains, and on that account their consideration is deferred 
to the section dealing with the general stratigraphic features of 
lacustrine deposits of peat. In this connection it is suggested that 
