From Introduction: "Figure 1 shows the location of sources that have been either exploited or seriously considered at one time or another, super-imposed upon a map indicating by small letters the order of consumption of K2O in the leading States; the amount used in these States, together with the percentage of the total consumption of potash used as fertilizer in the United States in 1939, is given in table 1. Figure 2 shows the domestic production and total consumption of potassium salts, in terms of tons of K2O, with the value per unit at the plants, for each year since 1913. Considered together, these two figures tell a significant story."

From Introduction: "The investigations presented in this bulletin have been undertaken by the bureau with a view to a better understanding of the conditions which confront the producer of commercial feldspar and also with the object of determining wherein the various deposits of feldspar differ."

Report issued by the Bureau of Mines over investigations conducted on manganese deposits in Maine. Details of the history, physical features, and geology are presented. This report includes tables, maps, illustrations, and photographs.

Report issued by the Bureau of Mines over studies conducted on manganese deposits of Aroostook County, Maine. Descriptions of the deposits, and the results of the study are presented. This report includes tables, maps, illustrations, and photographs.

Report issued by the Bureau of Mines over manganese deposits of Aroostook County, Maine. As stated in the introduction, "the work was undertaken to determine the extent of deposits largely concealed under glacial drift and to obtain subsurface sampled for manganese mineral identification and research in ore dressing and extractive metallurgy" (p. 1). This report includes tables, maps, and illustrations.

Report issued by the Bureau of Mines over studies conducted on manganese deposits in the Maple Mountain and Hovey Mountain area. The history, character, and physical descriptions of the deposits are presented. This report includes tables, maps, illustrations, and photographs.

Report issued by the Bureau of mines over studies conducted on beryllium deposits in New England. Evaluations of the deposits are presented and discussed. This report includes tables, maps, illustrations, and photographs.