The "three little crown things" separated by "25" are the barrel proof markings for an Enfield manufactured under commercial contract in Birmingham, England. The E.MARSON stamping, if it's on the bottom of the stock a couple of inches behind the trigger tang, is a stamp indicating the contractor/manufacturer who made the weapon.
"R" and "UR" may be the "VR" marking on the lockplate, typically stamped underneath a crown, standing for Victoria Regina. Most Birmingham guns had the year of manufacture stamped over the word “TOWER” on the lockplate, forward of the hammer. (For the trivia buffs, Enfields made at the Royal Small Arms Factory for British Army service were stamped with the year over “ENFIELD”, and the “TOWER” stamp on the lockplate indicates a commercially made contractor gun. British Army guns would also have the British Broad Arrow mark stamped forward of the TOWER stamp, but no exported Enfield (e.g., weapons bought by the Union or Confederate Army on the British arms market) had the Broad Arrow.)
There may (or may not) be a maker's cartouche stamped on the left side of the butt which would help confirm this as a Birmingham-made weapon.
The most Plain, Everyday, and Common (PEC) Confederate Enfield was the Birmingham-made, 1862 TOWER musket, followed closely by Birmingham weapons stamped 1861 TOWER on the lockplate. LONDON-stamped Enfields (made by the London Armoury Co.) were plentiful, but were outnumbered 2 to 1 by Birmingham weapons, and only began to arrive in the Confederacy in 1863.