23 June 1972
Vol 176, Issue 4041

About The Cover

Ice wedges developed in lake silts truncating glacially deformed, ice-rich Pleistocence sediments more than 40,000 years old. The ice wedge at the left is 4 meters wide at the top. Garry Island, Northwest Territories. See page 1321. [J. Ross Mackay, University of British Columbia, Vancouver]