Rock Compass: a New Aid for Collecting Oriented Specimens Bidgood, D. E. T. ; Harland, W. B. Abstract Publication: Geological Society of America Bulletin Pub Date: 1959 DOI: 10.1130/0016-7606(1959)70[641:RCANAF]2.0.CO;2 Bibcode: 1959GSAB...70..641B