In the preparation of the map many institutions and individuals have given cordial aid. The National Research Council, Washington, D. C., has sponsored the Committee on Glacial Map of North America and has extensively subsidized the travel expense of its members for meetings and conferences. The Geological Survey of Canada, the U. S. Geological Survey, and various State and Provincial geological surveys have co-operated in the project. The two surveys named first have supplied the Committee with all the base maps necessary for the glacial compilations. The U. S. Coast and Geodetic Survey has kindly supplied published and unpublished base data for the map. The Bureau of Geology and Topography, Ottawa, has calculated and plotted the base projection and has lent aid in the final design and lettering of the map. The American Geographical Society has borne the cost of the final manuscript draft of the assembled map. The Geological Society of America has borne the extensive cost and responsibility of publication and distribution. The use of the base for the inset map of the Northern Hemisphere is by kind permission of the University of Chicago Press.
Those individuals who have contributed glacial data to the map are named on the face of the map, and to all those persons, some of whom devoted much time to the project, the thanks of the Committee are due. We wish also to make special acknowledgment to F. J. Alcock, H. H. Beach, G. E. Ekblaw, E. D. Kindle, A. H. Lang, L. . . .