Jackson likely writes to Martin S. Garretson, (1866-1955), known for his study of and advocacy for the American bison, also depicted in Garretson's moving photogravures. Jackson begins the letter to Garretson. "Otherwise a 'Sinful Maverick': I had intended delivering this little picture personally...but an urgent request from Wyoming to be out there for some sort of an affair this coming week, will keep me so busy...that I must rely upon the mail to do the work for me...." Jackson then hopes his picture would find, "a place among the other 'old timers' ...." He signs, "W. H. Jackson," and in parentheses adds, "(Pawnee Bill?)" Garretson was called the "Sinful Maverick," and given the age difference between the two men, Jackson would be the old timer.
From 1870 to 1878 Jackson was the official photographer for the United States Geological and Geographical Survey of the Territories. His photographs of the natural beauty of northwestern Wyoming, taken during the Hayden survey expedition of 1871, were exhibited in the U.S. Capitol in Washington, D.C. and credited with having influenced the U.S. Congress to establish Yellowstone National Park in 1872. After he retired in 1924 from commercial photography, he traveled back to Wyoming for public appearances. In his official retirement, Jackson returned to painting on Western themes. It is possible that our letter was written during this later period and the picture Jackson mentions is a painting for Garretson. Martin Garretson, as a young man, traveled West to work as a rancher at the time the bison population was becoming depleted due to expanding settlements on the American plains. Garretson sought to reverse the decimation of the bison herds and eventually became one of the founders of the American Bison Society. He later served as its Secretary and eventually headed the department of Heads and Horns at the Bronx Zoo. During that time, he conducted the majority of the research for his book "The American Bison" (New York, 1938), which remains a standard reference on the species. Jackson's self reference as "Pawnee Bill?", the American showman, suggests association to the showman of the same name as well as to his photographs of the Pawnee tribe.