The geysers and hot springs of the Yellowstone are another proof of recent volcanic activity.

1943) pp. 365-376in JSTOR
Martin Geoffrey J. 1924)
"Climatic Change and Agricultural Exhaustion as Elements in the Fall of Rome" Quarterly Journal of Economics Vol.

He served as Presidents of the Ecological Society of America in 1917 the Association of American Geographers in 1923 and the President of the Board of Directors of the American Eugenics Society from 1934 to 1938. He taught at Euphrates College Turkey (1897–1901); accompanied the Pumpelly (1903) and Barrett (1905–1906) expeditions to central Asia; and wrote of his Asian experiences in Explorations in Turkestan (1905) and The Pulse of Asia (1907). He was on the original standing committee of the Foundation for the Study of Cycles from 1941.