Introduction.—For a decade attention has been turned to the continents. Through the distribution of animals and plants Wallace has studied the history of the former connection and disconnection of land areas. Theories of interchange of land and water have been propounded by Suess and Blytt. By means of geodetic data Helmert has discussed the broad relations of the geoid to the theoretic spheroid. Darwin has computed the strength of terrestrial material necessary to sustain the continental domes. James Geikie, treating nominally of coast lines, has considered the shifting relations of land and sea, and a half score of able writers have debated the question of continental permanence. The American Society of Naturalists, now holding its annual meeting at Princeton, N. J., devoted yesterday’s session to the consideration of such evidences of change in the geography of the American continent as are contained in the distribution of animals and plants. . . .