From Wiki:
Controversy: Yosemite Valley origins
While in California, Whitney became embroiled in two notable controversies. First, Whitney maintained that Yosemite Valley was created by a cataclysmic sinking of the valley floor. However, John Muir, who was exploring the Yosemite area during the same time, argued that the valley was carved by glacial action. Whitney derided Muir as an “ignoramus” and a “mere sheepherder.” Whitney's survey reports suppressed evidence of glaciers, and he never abandoned his viewpoint. Most scientists eventually dismissed Whitney's hypothesis and accepted Muir’s.
Controversy: Calaveras Skull
The second controversy involved the discovery of the Calaveras Skull, allegedly uncovered by a miner 130 feet beneath the surface of the earth. Eventually the skull made its way into the possession of Whitney, who quickly pronounced it genuine and concluded that it came from the Pliocene era (5.3 mya – 1.8 mya). However, others assert that the skull is much younger, as little as 1000 years.
Quite a difference huh? 1.8-5.3 mil or 1000 years lol. I said you can't trust dudes from 1870 who had no access to modern technology.