Land-Bridges across the Atlantic and Pacific Oceans during the Kainozoic Era

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My research work on the history of South America, its formation from several distinct land-masses and its relationship to other continents, pursued continuously since 1890, reached some degree of finality in my book on the Atlantic Ocean. As the results of these researches had not for many years received any recognition by geologists, it was particularly pleasing to me to find that in his presidential address on the same subject Prof. J. W. Gregory has expressed opinions which for the most part coincide with mine. In this most interesting account of his researches he brings together an astonishing number of facts, and in so doing arrives at the conclusion that until Miocene times the Atlantic Ocean was still spanned by an African-American land-bridge. This agrees with my conception of the conditions then prevailing, according to which the Upper Miocene beds of Entre Rios are the first in which marine mollusca, echinoderma, and selachia, derived from the northern and southern seas, mingle. Gregory, as well as C. Schuchert, rejects on geological grounds the drift theory of Wegener and A. L. Du Toit, as do all German geologists with whom I have been in contact. Wegener's hypothesis, so far as it relates to the Atlantic shores of Africa and South America, demands the permanence of the present form of these continents as far back as the Cretaceous epoch. Against this idea it must be noted that geology has never admitted the persistence of a long stretch of coast-line, 50 to 60 degrees