This paper emphasizes (1) the structure of the entire peat deposit down to clay, sand, or gravel, (2) the plants whose remains have formed the various kinds of peat, (3) the origin of the depressions in which the deposits have developed, and (4) the physical and chemical properties of the peat.
The 325 deposits which were investigated comprise over 50,000 acres and vary in depth from 3 to 63 feet. The kinds of peat in the order in which they commonly occur from top to bottom and the plants from whose remains they were formed are (1) moss peat from various species of Sphagnum, (2) fibrous peat mostly from sedges, (3) woody peat from logs, twigs and leaves, and (4) sedimentary peat frommicroscopic plants. Moss peat is absent in many deposits. The asociated mineral materials are mostly marl, diatomite (diatomaceous earth), and volcanic ash.
The depressions in which the deposits have developed were formed mainly by the activities of ice, water, or wind. A summary of the ranges and averages of pH, field moisture, ash, chemical composition and replaceable bases is tabulated. The types of soil on the deposits are Greenwood, Mukilteo, Spalding, Rifle, Tanwax, and Salt Marsh.
Data on chemical composition of the peat, including replaceable bases are given.