With just a quick search I found google books had Pioneer Photographers of the Far West: A BiographicalDictionary, 1840-1865 By Peter E. Palmquist, Thomas R.Kailbourn.
– side note I had the honor of writing back and forth with Mr. Palmquist before he passed. He was so generous with his time and knowledge. He invited me to visit to gain some knowledge on a family photographer and not going has been one of my biggest life regrets. -
There's quite a discussion on John A. Todd here and tells of him being at this address from 1880-1884. How's that for dating a photo? If they were only all that easy! But I was lucky not all of the book is online this part just happened to be.