The U. S. Geological Survey has recently measured and sampled the Phosphoria formation at many localities in Idaho and other western states. These data. will not be fully synthesized and analyzed for several years, but segments of the data, accompanied by little or no interpretation, are published as preliminary
reports as they are assembled. This report, which contains abstracts -of many of the sections measured in southeastern Idaho (fig. 1), is one of this series and is the fourth report on Idaho; it includes about half the data gathered in Idaho in 1949. The field and laboratory procedures adopted in these investigations are described rather fully in a previous report (McKelvey and others, 1953a).