IDDINGS, Joseph Paxton, geologist, born in Baltimore, Maryland, 21 January, 1857. He was graduated at the Sheftield scientific school of Yale in 1877, and subsequently studied analytical chemistry there, while serving as assistant in mechanical drawing and surveying. Subsequently he studied geology under Professor John S. Newberry, at Columbia, and spent the winter of 1879-'80 in Heidelberg, working in microscopic petrography. In July, 1880, he was appointed assistant geologist on the United States geological survey, under Arnold Hague. His scientific papers, published in the "American Journal of Science" and the "Bulletin" of the United States geological survey, include "Notes on the Volcanoes of Northern California, Oregon, and Washington Territory" with Arnold Hague (1883); "The Columnar Structure in the Igneous Rock on Orange Mountain, New Jersey" (1886). and "The Nature and Origin of Lithophysae and the Lamination of Acid Lavas" (1887).