Indeed it's barrel is marked "Fine Laminated Steel S Sutherland"
"side plates" are marked "GH Ferriss Patent" on one side and "October 10 1871" on the other.
It has a "bolt" (seen in the standing breech)that sweeps back (at the bottom)when the top button is pushed, allowing the barrels to open. Mine has been poorly restocked but is in nice condtion other than that. Ross