Correction re when Patrick Breen was transferred to 1st Cavalry, G Troop. Reviewed Camp Lowell, A. T., records and discovered Private Patrick Breen's transfer from Camp Bowie, A. T. to Camp Lowell, A. T. Said record indicates this the order was received Feb 9th '71. [Fairly certain the date is incorrect, as you will see below record indicating the 1st Cavalry, Troop "G" departed Arizona Territory on 04 February 1871.
07 June 1871, HQ of the National Div. of the Pacific gave orders to transfer Private Fisher Clifford Book Troop G. 1st Cav to Co. D 21 Infantry and Private Patrick Breen Co. D 21 Infantry to Troop G, 1st Cavalry.
Discovered on Camp Lowell A.R. military returns, "PURPORT" Record, signed off by Thos. Dunn, Captain, 21st Infantry. Commander of the Post.
" The 1st Cavalry, G Troop, was ordered per G.O. 3 Hd. Qtrs. Mil Div of the Pacific and San Francisco CA, Jan 6th, 1871, Capt R. F. Bernard 1st Cav'y [with 2nd Lt. L. G. Klye 1st Cavy] and his Troop "G" 1st Cavy proceeded Feb 4th 1871, Enroute to San Francisco, Cal. for assignment to duty." [discovered on RECORD of EVENTS, Camp Bowie A. T. , February 28th, 1871.
One can follow the 1st Cavalry's timeline to see where Private Patrick Breen may have been in a certain time line, since he .. according to family lore .. remained with the 1st Cavalry until he retired from service in the U.S. Army.