The third Yale College Scientific Expedition was the smallest of the 4 student expeditions that O.C. Marsh
took into the field. The plan of attack was to work the Cretaceous
chalk around Fort Wallace and then later move base of operations to
Wyoming. An Army escort commanded by Lieut. James W. Pope, and the
assistance of Ed Lane as guide, were secured before the party set out
from Fort Wallace that summer.
The early portion of the field season, in Kansas, was especially successful. Specimens of both Hesperornis and Ichthyornis were discovered.
The later half of the field season, in Wyoming, was not as successful as Marsh’s previous expeditions. The party was escorted by a detachment of the Ninth Infantry headed by Lieut. Jesse M. Lee from Fort D.A. Russell. Little information is available about this part of the expedition, but the Peabody’s accession ledger records that the Museum received from the expedition “Tertiary fossils” from the Green River Basin.