My Ancestors also came from Calhoun Co ILL Area. Grigsbys, Mulkeys, McGees, Reeves, Turner or Haines. I have found most of this in the Calhoun Co. ILL Census. Not sure if this is the Sievers you are looking for as some of your dates don't match mine. Hope this helps.
Bernard Sievers b 1867 ILL m Catherine Pluestar b 1875 ILL. married 27 Apr 1897 Calhoun Co ILL.Children are John B b Apr 1898 - Mary C b May 1899 - Standislaus Sievers b 1901 - Ferinand b 1902 ILL - Leonard b 1903 ILL Henry B b 1904 - Carl Sievers b 1906 - Albert H b 1908 ILL - Joseph B b 1910 ILL - Lawrence b ? - Fay b ? - Ben b ? - Elmer b ?I am not directly related to the Sievers, just branched out to far. My line goes back from Sievers to Plustar, Klaas then to my family McGee's.