Joseph Butler, born in England, had been in business with James Golcher, also born in England, in Philadelphia. Together they formed basis of Golcher's Eagle Gun works.
Butler moved to Chicago about the same time that William Golcher moved to St. Paul, early 1850's. For a time Thomas L Golcher and his brother worked for Butler in Chicago
Purdey Thumb Hole actions were used as a base for many Illinois makers-Donn,Fred Abbey, George Abbey, Joseph Butler and Thomas. So it almost certain that Butler was importing actions from both Scott and Purdey.
Your gun, while not rare, is not very common.
Pete
