5. 6. Weed, W. H., "Geological Sketch of the Hot Springs District of Arkansas."-Fifty-seventh Congress, First Session, S. Ex. Doc., 282:79-94. Reprinted by the Department of the Interior, 1902. Obtainable from National Park Service, Washington, D. C. 1905 Boltwood, Bertram B., “On the Radioactive Properties of the Waters of the Hot Springs on the Hot Springs Reservation, Arkansas."—American Journal of Science (4) 20:128-132. Obtainable from the American Journal of Science, New Haven, Conn. Weed, W. H., "Notes on Certain Hot Springs of the Southern United States."-U. S. Geological Survey Water Supply Paper No. 145, pp. 185206. Now out of print, but may be consulted in public or scientific libraries. 1909 7. Dole, R. B., "The Quality of Surface Waters in the United States, Part I, Analyses of Waters East of the 100th Meridian," Water Supply Paper No. 236 of he U. S. Geological Survey. Now out of print but may be consulted in public or scientific libraries. 1910 8. Purdue, A. H., "The Collecting Area of the Hot Springs of Hot Springs, Arkansas."-Indiana Ac. Sc., Tr. 1919, pp. 269-275. Journal of Geology, 18:278-285. Obtainable from University of Chicago Press, Chicago, Ill. 1911 9. Purdue, A. H., "Recently Discovered Hot Springs in Arkansas.” Journal of Geology, 19:272-275. Obtainable from University of Chicago Press, Chicago, Ill. 1914 10. Clarke, F. W., "Analysis of Potash Sulphur Spring Water, Garland County Arkansas," Water Supply Paper No. 364, of the U. S. Geological Survey. Obtainable from U. S. Geological Survey, Washington, D. C., for 5 cents. Also contains: Riggs, R. B., "Analysis of Water from the Happy Hollow Spring, Hot Springs, Arkansas." Stokes, H. N., “Analysis of Water from the Mountain Valley Spring, Near Magnet Cove, Ark." Whitfield, J. E., “Analysis of Water from the Hominy Hill Springs, Arkansas." 1923 11. Purdue, A. H., "Description of the Hot Springs, Arkansas, Quadrangle."-U. S. Geological Survey Folio 215. Obtainable from the U. S. Geological Survey, Washington, D. C., for 25c. MINERAL FERTILIZERS There are certain mineral substances which are essential to plant life. When any of these substances are entirely absent, plants cannot grow. Among those elements which soils most commonly lack are nitrogen, phosphorous and potassium. Nitrogeneous salts are found in guano and resultant leached salts. in very limited amounts and are seldom of commercial value. Acid phosphates may be produced by chemically treating the rock phosphates described later. Potash occurs in the glauconite of the greensands. Soils frequently become acid, and this acid retards plant growth. The application of raw or burnt limestones, chalk or chalk marl will neutralize the acids in the soil and thus aid plant growth. The basic quality imparted to the soil by slight excess of lime will permit the more rapid growth of nitrogen-forming bacteria, and so liming a soil indirectly leads to the conservation of nitrates. Gypsum is a hydrous calcium sulphate and it does not neutralize an acid soil. It does aid in precipitating the colloids in a clayey soil and thus reduces the tendency to "puddle" when wet and get "lumpy" when dry. It supplies sulphur and calcium to plants, and, when mixed with barnyard manures, it saves nitrogen by preserving the ammonium as ammonium sulphate. Lack of comprehensive surveys and development work make it impossible even to approximate the extent of Arkansas' resources in the matter of minerals suitable for fertilizers. It is definitely known, however, that in variety, quality, and quantity these minerals are of great potential value, perhaps exceeded only by petroleum, coal and bauxite. The heavy consumption of fertilizers in this State is shown by the report of the Department of Conservation and Inspection of sales of fertilizers made in the State during the year ending June 30, 1926: In the northern part of the State large areas of limestone and dolomite await development. In the southwestern part of the State, gypsum and chalk are abundant, while phosphate rocks outcrop in numerous places in Independence County, in north-central No. Arkansas and also in Izard, Stone, Searcy, Baxter, Marion, Newton, Boone and Carroll Counties. The four principal types of mineral fertilizers occurring in Arkansas will be discussed separately. These are chalk, chalk marl, greensand marl, limestone, phosphate and gypsum. Chalk and Chalk Marls The chalk beds of Arkansas have been treated under "Chalk" and will not be discussed here. Marls are rather soft, friable rocks, consisting principally of calcium carbonate. There are two important types in Arkansas which are chalk or lime marl, and greensand or potash marl. The distribution of the chalk or lime marls is shown on the map of the chalk area of southwestern Arkansas. The lime and sandy content in these marls can be usually regulated by selecting portions of the marl beds which are either low or high in lime and sand as required. The lime marls in Clark, Hempstead, southern Howard and Sevier Counties are of a great variety of composition and practically unlimited as to quantity. The essential ingredients of these lime marls are calcium carbonate, usually in a chalky state, ferric oxide and magnesium carbonate and, in addition, sand and clay. The following are twelve analyses of the chalk marls in the vicinity of Washington, Okolona and Deciper. *Taken from the Twenty-second Annual Report of the U. S. Geological Survey for 1900-1901, Part III. "Chalk of Southwestern Arkansas," by Joseph A. Taff. Magnesia, MgO Carbonate of Lime, CaCo2 Carbonate of Mag nesia, MgCO3 For bibliography of "Chalk and Marls" see "Bibliography of "Chalk." The chalk marls meet all fertilizer requirements that are met by limestones. The location of these deposits in southwestern Arkansas. in an area removed from other limestone beds makes these marls a distinct asset to that part of the State. Greensand Marl Greensand or glauconitic sand contains potash in the form of the potash mineral glauconite. Greensand marl is found along the Little River in Little River County near Morris Ferry in considerable quantities and also in the vicinity of Washington, Hempstead County. So far as is known these two greensand areas have not been specifically mapped. Analyses of greensands from near Washington are as follows: According to N. F. Drake* if an application of fifty tons per acre of greensand marls of the equivalent composition of an average of six samples analyzed were added to the soil, there would be added to the acre the following amounts of materials which would, under normal conditions, supply plant requirements for years: Potash Lime Magnesia 1,160 pounds 5,790 pounds .1,130 pounds Bibliography of Greensands 1918 1. Ashley, G. H., "Notes on the Greensand Deposits of the Eastern United States."-Bulletin No. 660 of the U. S. Geological Survey, pp. 2749. Now out of print, but may be consulted in public or scientific libraries. Also contains: Hicks, W. B., and Bailey, R. K., "Methods of Analysis of Greensands." †U. S. Geological Survey Bulletin 6606, "Notes on Greensand Deposits of Eastern: United States," by G. H. Ashley. N. F. Drake, "Mineral Fertilizers in Arkansas."-Published by the Arkansas State Bureau of Mines, Manufactures, and Agriculture. 1924 2. Drake, N. F., "Mineral Fertilizers in Arkansas."-Obtainable from Bureau of Mines, Manufactures and Agriculture, State Capitol Building, Little Rock, Ark. Limestones (See also "Building Stone" and "Lime for Burning" The limestones of the State constitute the most abundant available type of mineral fertilizer material. For the purpose of this discussion, limestones and dolomites may be grouped together. They are Batesville White Lime Company Quarry, Near Ruddles, Ark. used in both the raw and burned form. When used raw the effects are not noticeable at such an early date as is the case when burned but these effects will be spread over a longer period. Because of their great abundance and wide distribution in the northern and southwestern part of the State, the development of these limestones will be limited largely to small plants supplying only a local limited trade. Some few such plants are now in operation, but there is need and opportunity for many more. The distri |