help with military button ID - California

[sendin]

Found this at an old roadhouse site. The roadhouse was in use in the 1840's and 1850's from what I've been told. After that it was a residence. It is located about 60 miles north of San Francisco. This was found in back of where the roadhouse building stood. Sorry that these pics aren't better. The back reads 'something' "& SON CO" and then there's two dots. Behind the lettering is a pattern of closely spaced raised dots. It is a two piece design. The eagle has a shield with arrows on the right and olive branches on the left.

 

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[PBK]

U.S. General Service button, c. 1854-1902. Can't read enough of the backmark to identify the maker, as there are a number of "_____SON & CO." marks from that period.

 

[sendin]

Thank you very much!