00951cam a22003011 4500 gs 61000031 DLC 20260227111410.0 720222s1959 xx 000 0 eng gs 61000031 (OCoLC)245741 DLC OAkU DLC premarc QE185 .A43 no. 54 Geological Survey of Canada Helicopter operations of the Geological Survey of Canada. [Ottawa] Dept. of Mines and Technical Survey, Canada [1959] xi, 60 p. illus., maps, diagrs., tables. Its Bulletin 54 Abstract in English and French. Includes bibliographies. Helicopters. Geology Fieldwork. Geology Canada Maps. Photographic surveying. Geology Canada Surveys. Bulletin (Geological Survey of Canada) ; 54. 29511 29511