Timothy O'Sullivan was a photographer who covered the WBTS. As a teenager hr worked in Mathew Brady's studio. This is some of his post war work covering exploration of the West. If you enjoy Native American history you'll get a special kick out of the pics as well.

http://www.dailymail.co.uk/news/article-2149899/The-American-West-youve-seen-Amazing-19th-century-pictures-landscape-chartered-time.html?ITO=1490