Edward Drinker Cope
Cope also looked for fossils in the west of the United States. In 1872 he explored Eocene rocks. The rocks were 55 to 38 million years old. That year, he worked too much and had a breakdown.p583 In 1873 he studied the Titanothere beds (strata) of northeastern Colorado. Titanothere was a large extinct herbivore.p183/194