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, DEPARTMENT OF PUBLIC WORKS 223 L ( conteilt of the sixth foot is about like that of the third foot in the Grundy and Holdrege series. Wabash. A characteristic feature of the topography from Norman on the ~ast to Bertrand on the west is depressions 'of a few acres up to one or two square miles in extent. These lie at an elevatioh of a few feet up to 20 feet lower than the surrounding land. The surface drainage accumulates in these areas and in wet season.. they are filled with water, tho in dry seasons they are usually all dry. Except in the' interior of the larger areas, this land is generally all farmed. This soil is classified in the Wabash series. It is a black clay loam at the. surface growing heavier and more tenacious in the second or third foot. Uusually it. changes in the fourth or fifth foot to the friable silty-like materiai of the loess. .The origIn' of this is sedimentary. The finer clayey or silty material of' the sur- rounding land has been carried in by the runoff, and deposited. No mechanical analysis has been made of any of this soil but the hygro- scopic coefficient and the moisture ;equivalent of some typical samples are shown in Table 11. According to the Phelps County Soil Surve), about ten per cent of the Plains land in that country consists of such depressions. Soil Studies. Ie:' " The information concerning the soils of this area was obtained first hand thro field examinations, and laboratory studies. In addi- tion there' is' available for correlation the Soil Survey of Phelps County (6), a reconnaissance map by the. Department of Conservation and Soil Survey, and studies by Alway et al (1) on this portion of the loess region. In connection with this report numerous trips were made over one portion or another of the area. Three hundred and tw.enty-six soil samples were collected at different points. Hygroscopic coefficient determinations were 'made on all of. the samples, moisture equiva- lents on 206 samples, mechanical analysis on 30 samples, nitrogen on 17 samples, weight per cubic foot, to six feat, at 5 points and profile examinations to six feet in all important soil types. Critical studies oil the probable tilth of the soils were made on 25 samples. Weight per Cubk Foot. In order to convert the moisture data in per cent shown in later tables to inches of water,it is necessary to' know the weight per cubic foot of the different soil types in the area, accordingly this determination was made. The "pit method" was used, the six foot pits which were opened being useful in studying the soil profile. The soil was removed in 6-inch sections with a rigid thin walled 4-inch brass cylinder. Weights per cubic foot were determined at Hastings - College,' Kenesaw, Norman, Holdrege and Bertrand, each in .close vici nity to the. saturation plats described later. The data obtained are shown praphically in Figure 8. ,. .