HE WAS MOST FAMOUS FOR DISCOVERING VARVES OR ANNUAL LAYERS OF SEDIMENTARY ROCK AND PIONEERING THEIR USE IN GEOCHRONOLOGY AND HIS RECOGNITION OF THEIR POTENTIAL IN ESTABLISHING ANNUAL CHRONOLOGIES OF PAST CLIMATIC AND ENVIRONMENTAL CHANGE
BARON GERARD JACOB DE GEER (1858-1943) SIGNED QUOTE, “Gerard DeGeer, New York, Nov. 24, 1920”, on a card 4.25 x 3.5, by the Swedish geologist who made significant contributions to Quaternary (the current and most recent of the three periods of the Cenozoic era in the geologic time scale) geology, particularly geomorphology and geochronology and is best known for his work on varves (annual layers of sediment or sedimentary rock). He was a professor of general and historic geology at Stockholm University and went on to become its president (1902-10). In 1940 he published his longest and best-known work: Geochronologia Suecica Principles. His handwritten quote, in full: “Aude et caude!” The card is in fine condition, with minor age toning.