Henry Fairfield Osborn’s work with the AMNH began in 1891 when he was appointed as mammal paleontologist. He later served as AMNH president from 1908-1933. As president, Osborn oversaw multiple AMNH research expeditions including a journey to the Gobi Desert to search for evidence of human evolution. Osborn was known for his non-Darwinian theory of human evolution—he theorized that humans did not evolve from apes but that they evolved parallel to and apart from other ape species ("Henry Fairfield Osborn: Race and the Search for the Origins of Man" by Brian Regal). Osborn hoped the Gobi expedition would uncover new evidence to support his theory of human evolution; instead, the team uncovered new dinosaur fossils, including the first discovered dinosaur eggs, and Cenozoic mammal fossils. (AMNH Timeline & AMNH Paleontonlogy)
The Dakota formation is a sedimentary rock deposit which stretches all the way across the North American continent, from British Columbia to the Great Plains. Its colorful formations preserved many organisms, including fossilized leaves. (Wikipedia)
Tiffany & Co. is an American luxury jewelry company which was founded in 1837 by Charles Lewis Tiffany and John B. Young. The letter opener might be a product of Design Director, Louis Comfort Tiffany's art nouveau period. (Tiffany & Co.)
Marked “Tiffany 8cm/Markers/M” CA 1900, Bronze.
103/4 Long, 2 1/8” Wide (at head), 3/16 Thick.
Mounted in the head of the opener is a fossil leaf (possibly from the Dakota Formation). The opener belonged to Dr. H.F. Osborn (1857-1937).