History of the Map
The Glacial Map of North America embodies the first attempt at representing the Pleistocene glacial features of North America in considerable detail and on a large scale. The earlier maps, though useful for their times, were, with one exception, published on a small scale. That exception (T. C. Chamberlin’s excellent 1913 wall map, scale 1 inch = 104 miles) did not attempt to differentiate the several drift sheets nor to plot the directions of glacier flow other than in a very generalized manner. Among the small-scale maps, the compilations of Antevs, published in 1929, are noteworthy for the amount of drift-border detail they show, although they did not represent the whole of North America on a single map.
The following is a list of published glacial maps of North America. Those which appear in textbooks of geology, those which show only a part of North America, and those which show glaciers in restored form, instead of glacial-geologic features, are not included.
Lewis, H. C. (1894) Glacial geology of Great Britain and Ireland, Longmans, Green & Co., London, plate opp. p. 4. 9 × 8½ inches. Scale: 1 inch = 630 miles. Colored.
Dana, J. D. (1895) Manual of geology, 4th ed., American Book Co., New York, Fig. 1548. 8½ × 6 inches. Scale: 1 inch = about 500 miles;
Upham, Warren (1895) The Glacial Lake Agassiz, U. S. Geol. Survey, Mon. 25, pi. 16. 9½ × 6½ inches. Scale: 1 inch = about 550 miles. Colored.
Leverett, Frank (1899) The Illinois . . .