146 NATIONAL ACADEMY OF SCIENCES 
where he afterwards occupied the chair of geology until 1876, 
at which time he became professor emeritus. He was appointed 
assistant geologist in the geological survey of the Fourth District 
of New York in 1836, and the following year, as geologist, was 
placed in charge of the work of this western district. He pub- 
lished reports annually from 1838 to 1841, and in 1843 a final 
report in quarto form—one of the series of volumes on the 
natural history of the State printed by order of the Legislature. 
In this, the fossils, the lithological characters of the rocks, and 
the succession of the strata are fully described. The same year 
Hall was appointed paleontologist of the State and continued in 
that position until 1874. The principal work of these years is 
embodied in the eight volumes of the ‘“ Paleontology of New 
York” which has been described as “ one of the most remark- 
able monuments of scientific labor, zeal, and industry, which this 
country has produced.” In order to trace the western extension 
of the New York strata, Hall studied the formations of the 
Mississippi Valley and the Rocky Mountains. In 1855, he was 
appointed Geologist of Iowa, and in 1857 Geologist of Wis- 
consin, and the results of his western investigations are largely 
embodied in the reports of the surveys of those States. In 1858, 
he received the Wollaston Medal of the Geological Society of 
London, of which he was a foreign member. At about this time 
he took up the study of the graptolites of the so-called Quebec 
group, and in 1865 published an elaborate monograph in the 
20th Report of the New York Cabinet of Natural History. He 
was the Director of the New York State Museum from 1866 to 
1893. 
In 1876, he aided in organizing the International Congress of 
Geologists, and was Honorary President of the Congress held 
in Washington in 1891. He was also the first President of the 
Geological Society of America in 1889. 
In addition to his work on the paleontology of New York, 
Professor Hall wrote the paleontological portions of the reports 
of various surveys of the Western Territories under the Govern- 
ment, including those of the Frémont Expedition, the Stansbury 
