James Dana

Born Feb. 12, 1813. in Utica, New York; died Apr. 14. 1895, in New Haven, Conn. American geologist.

Dana graduated from Yale University in 1833. He was a professor of geology and mineralogy at the university in New Haven from 1855 to 1892. In 1837 he devised a chemical classification of minerals, which remained substantially unchanged until the end of the 19th century. In 1873, Dana proposed the terms “geosyncline” and “geanticline.” He believed that the great downwarps in the earth’s crust and the formation of folds were caused by a contraction of the earth’s crust as a result of the globe’s cooling and contraction. According to Dana, the ocean floor subsides and exerts pressure on the continents, as a result of which downwarps (geo-synclines) and uplifts (geanticlines) form along the coasts of the continents. Great thicknesses of sedimentary rock accumulate in the geosynclines. Further crustal contraction leads, according to Dana, to the crumpling of the sedimentary layers into folds and to their being squeezed up in the form of mountain ranges. In the theory of the evolution of the organic world he introduced the empirical principle of “cephalization,” according to which the development of animals moves in the direction of a more complex nervous system from the lowest organisms to the highest.