00781cam a22002411 4500 gs 62000273 DLC 20260227111411.0 740920s1962 xx 000 0 eng gs 62000273 (OCoLC)1017665 DLC NRU OCoLC DLC premarc QE133 .P46 Perry, Eugene S. (Eugene Sheridan), 1892- Montana in the geologic past. Butte, Montana School of Mines, 1962. vi, 78 p. illus., port., maps (1 fold.) diagrs., tables. 28 cm. Montana. Bureau of Mines and Geology. Bulletin 26 Bibliography: p. 77-78. Geology Montana. Montana Bureau of Mines and Geology. Bulletin ; 26. 29649 29649