They are lovely photos, but I think you have the dates wrong. Yosemite wasn't really discovered by folks from the eastern United States until the Gold Rush times, which would be the late 1840's and 50's. It didn't become a state park until the 1860s and a national park in 1890. Therefore, I would assume the photos were done in the late 19th century or in the early 20th century.

Larry Spencer