00970cam a2200277 4500 gs 67000323 DLC 20260227111421.0 700407s1967 nduab b 00010 eng c gs 67000323 //r84 U.S. Geol. Survey. Library QE149 .D67 QE149 .A23 no. 52 Copy 2. Dow, Wallace G. The spearfish formation in the Williston Basin of western North Dakota, by Wallace G. Dow. Grand Forks, N.D., 1967. ii, 28 p. illus., maps. 23 cm. North Dakota. Geological Survey. Bulletin 52 Part of the illustrative matter fold. in pocket. Bibliography: p. 27-28. Geology North Dakota. Geology Williston Basin. Geology, Stratigraphic Permian. Geology, Stratigraphic Triassic. Bulletin (North Dakota Geological Survey) ; 52. 30397 30397