S.M. possibly stands for Sylvester Matz. Sylvester Joseph Matz was born 11 January 1881 and died 21 October 1974. Waseca business: EACO, aka City Roller Mills. White Rose and Waseca Flour. Everett, Aughenbaugh & Co., Proprietors, Manufacturers of White Rose and Waseca Flour, Waseca, Minnesota