Five sets of 'close' samples (narrow and contiguous samples across a lithologic
unit) from beds of high phosphate content of the Phosphoria. formation in Idaho, Utah, and Wyoming were analyzed chemically for F and C02. Very good correlations between F, C032, and P205 were found in several of the samples.
The size of phosphate pellets was measured in thin sections of two sets of close samples. Frequency histograms and cumulative curves were plotted from these size measurements, but when compared with uranium concentration for each
sample, no significant correlation between size and uranium concentration was
Analyses of these samples for P2O5, CaO, organic matter, and equivalent ura-
nium are presented in a previous report by this writer (U. S. Gool. Survey Bull. 988-D). In two sets of samples a good correlation was found between equivalent uranium and each of the other components. The samples in these two sets have a uranium content that is relatively high for the Phosphoria formation, and they show considerable range in P205 content.