Early photographer Timothy H Sullivan is one of a number of pioneering recorders of the west in the 1860s and 1870s. Sullivan was probably born in New York in 1840 to immigrant parents but some sources say he was born in Ireland and brought to America in 1842. He apprenticed to well known portrait photographer Matthew Brady in the 1859-62 time period. Brady was born in upstate New York near Lake George in 1925, but he also said in later years he was born in Ireland. While Brady continued taking portraits of soldiers heading off to war, he hired Sullivan and a number of other to take pictures of field military and post battle scenes in the civil war. Brady financed the field photos himself, going into debt to do it, expecting to be able to sell his photos to the government after the war. However the post war congress was parsimonious and balked at purchasing the photos. Brady went bankrupt and died a pauper.
After the war, Sullivan became part of the US Geological Survey which mapped the west from 1867 to 1874, and took a number of iconic photos of the Comstock, Yosemite and geological formations throughout the west. He remained with the survey but not much else is known about him and he died in New York in 1882. His photos sell for tens of thousands of dollars today, but like Brady, he saw no benefit in his lifetime.
Reno based Geologist and avid photographer, Kelly Cluer, has done some amazing work researching the original photos of Sullivan and other early western photographers like Carlton Watkins. This work has been documented in a number of presentations for the Mining History Association. The links are attached and are well worth watching.