paleontological department of the survey of Canada, under Sir William Logan, but undertook the study of the graptolites of the Quebec group, and published a monograph on them, which was afterward republished, with additions, in the "Twentieth Report of the New York State Cabinet of Natural History." The list of his other contributions to American geology includes articles in the reports of the "State Cabinet and State Museum"; "Descriptions of Organic Remains," given in the Goverament reports of various Western surveys, including the reports of Fremont, Stansbury, and the boundary survey of the United States and Mexico; and numerous contributions to the "American Journal of Science," and to various scientific societies at home and abroad. He is a foreign member of the Geological Society of London, and received the Wollaston medal from it in 1858; and is a corresponding member of the Institute of France. M. Ch. Barrois, reviewing in the "Revue Scientifique" the latest published volume of Professor Hall's "Paleontology," says that, like all the other publications of the author, it "brings an ample harvest of new and important facts. It would form the base and the foundation of the study of the palaeozoic bivalves, if it did not have to share that honor with the work recently published by our regretted compatriot Barrande, on the 'Acephalæ of the Silurian of Bohemia.' Never will the names be separated of these two superior men, who have devoted themselves during this century with an equal activity to the study of the palaeozoic faunas. Born in countries distant from each other, in environments still more widely separated in modes of thought, Barrande and James Hall came to fill the same part in the history of science. The same love of research and of the truth animated them; the same indomitable energy constantly encouraged and sustained them; and, with all the work that has been accomplished by numbers of other specialists, every one will recognize that these two men have competently described the fauna of the transition-beds. They have done more in that direction than all the rest of their generation."
Professor Hall devoted much attention to the study of crystalline as well as of fossiliferous stratified rocks, and was, according to Dr. Hunt, the first to point out the persistence and significance of mineralogical character as a guide to their classification, in the manner which has since been developed and extended by the latter geologist. Among his other most important contributions to geological science is his suggestion of a rational theory of mountains, in regarding them as the products of erosion, aided by the upheaval and contortion of strata as an incidental, not a chief factor.
The magnificent collection of fossils accumulated by Professor Hall during the course of his geological work has been transferred to the American Museum of Natural History, and now forms a part of the cabinet in the New York Central Park.
