Postby Joerg » Wed Nov 12, 2014 3:26 pm
Theo is right. It is Siders - Sierre in the Canton of Valais, Switzerland. Alain Gruber in "Weltliches Silber I" attributs the maker mark as unidentified, but probably a descent (son) from Paul Domenikus Schell, died 1716. Your spoon looks first half of the 18th century. So this would fit.
Regards
Jörg