The ice age in North America and its bearing upon the antiquity of man5th edwith many new maps and illus., enland rewritten to incorporate the facts that bring it up to date, with chapters on Lake Agassiz and the Probable cause of glaciation . for the Advancement of Sci-ence, vol. x.\xi, p. 328; also Upham, in Geology of New Hampshire, vol. iii. + See Geology of New Ilainpshirc, vol. iii, pp. 3-177; also, AmericuiJournal of Science, vol. cxiv, 1877, p. 459. 346 THE ICE AGE m NORTE AMERICA. terraces—being newer than the till and older than the ter-races. On going over the ground in 1881 with Mr
The ice age in North America and its bearing upon the antiquity of man5th edwith many new maps and illus., enland rewritten to incorporate the facts that bring it up to date, with chapters on Lake Agassiz and the Probable cause of glaciation . for the Advancement of Sci-ence, vol. x.\xi, p. 328; also Upham, in Geology of New Hampshire, vol. iii. + See Geology of New Ilainpshirc, vol. iii, pp. 3-177; also, AmericuiJournal of Science, vol. cxiv, 1877, p. 459. 346 THE ICE AGE m NORTE AMERICA. terraces—being newer than the till and older than the ter-races. On going over the ground in 1881 with Mr. Uphamsnotes in his hands, Professor Dana concluded that what had called kames were in reality a portion of theregular terrace formation. In Professor Danas view, thereputed kames are merely the coarser part of the terracematerial accumulated in excessive amount in the larger val-ley wherever tributary streams brought into it their heavierburdens from the higher land. On this theory, the heightof the Hoods in numerous localities must have been betweentwo hundred and three hundred feet above low water in theriver ; for in various places these deposits are at that heightabove the river. But upon the supposition that they aie. Semgated teiihioJower portion^ 37S ft- above sea. Fig. 106.—Section east from Ledyard Bridge, Hanover, New Hampshire, ehowins: segre-uteU veins in the lower portion. Length, about seven hundred feet. Height oftame above the river, one hundred and forty feet. (Upham.) kames, deposited when the ice itself formed barriers to keepthe streams in various abnormal positions, the glacial floodswould not need to be more than from one hundred to onehundred and fifty feet in height, since that is all that isrequired for the deposition of the highest river-silt whichoccurs. It must be confessed that Professor Danas estimates ofthe size of the Connecticut Piver floods at that time aresomewhat startling, even with al> the changes of level forwhich he prov
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