Geology and water resources of a portion of the Missouri river valley in northeastern Nebraska . of the formation falls to Avithin 8 or 10 feet of- theriver at Wheeler and Xieveen, S. Dak. For most of the distance,from a point 5 miles below Greenwood to Yankton, the Niobrarabluffs are prominent on one side of the ri^^er or the other. At a num-ber of places slight faults and flexures Avere observed; most of thelatter occur at the mouths of small ravines and appear to be causedby the sAvelling of beds. The steeper slopes are often covered Avithsplinters of chalk rock broken from the cliffs above
Geology and water resources of a portion of the Missouri river valley in northeastern Nebraska . of the formation falls to Avithin 8 or 10 feet of- theriver at Wheeler and Xieveen, S. Dak. For most of the distance,from a point 5 miles below Greenwood to Yankton, the Niobrarabluffs are prominent on one side of the ri^^er or the other. At a num-ber of places slight faults and flexures Avere observed; most of thelatter occur at the mouths of small ravines and appear to be causedby the sAvelling of beds. The steeper slopes are often covered Avithsplinters of chalk rock broken from the cliffs above. Section of Xiohrara limestone and (is-sociated ;i northeast of St. James, Nehr. Feet. Loess. Rises in hills to an altitude of over 1,400 feet 40-50 Niobrara chalk, massive, somewhat sandy, and harder in lower at 1,205 feet above sea level. Rises in hills to an altitude of 1,335 feet, or a thickness of 130 feet exposed 40-50 Carlile clay, dark and bluish, with some sand and sandstone. Large cal-careous concretions 50 to 55 feet below top. Exposed in slope to river_ 71. DESCRIPTION OF THE ROCKS. 15 Section of Niohrara Jimestone and Pierre f^hale on Bazilc Creek at bend in road 1 mile south of Bazile Point, shale: clay, dark in bank, lijj^hter on weathered surface,which is strewn with selenite crystals and small yellowish con-cretions of irrejrular form 6 Niobrara : Weathered chalk, yellowish, with 8 or 4 li^ht-colored streaks 2 inches thick and about 1 foot apart, O. eonyesta present 7 Chalk, beds irregular, sandy, and at places concretionary; gypsumplates occur in bedding and irregular joint planes. Lower beds 0 to 8 inches thick. O. congesta is the common fossil 8i Blue chalk, lower 4 feet in 2 beds; large Inocerami and 0. coti-gesta present 8 Analysis of Niobrara chalk rock.[Howison Crouch, analyst.] Unweatheredspecimen. Weatheredspecimen. Moisture Trace. SiOo SOs .85 CO2
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