Hello Bobbi,
1. Sillium is a village which belongs to church parish of Bockenem and the community of Holle in the county Hildesheim.
2. Sehlde Krs. Marienburg belonged to the county of Wolfenbuettel (territory Braunschweig) also like parts of the cummunity of Sillium, Wartjenstedt, Binder, Rhene, Baddeckenstedt, Groß Elbe, Klein Elbe, Gustedt, Groß Heere, Klein Heere, Sehlde. Today it belongs to the county of Hildesheim (sourc: de.wikipedia.org/wiki/Kreis_Marienburg). This would be the correct micro fiches for Sillium, Groß and Klein Elbe.
Sehlde Krs. Gronau: This is different from the other town with the same name. The former county of Gronau belonged to the county of Alfeld/Leine. To the county of Gronau belonged the villages of Esbeck, Deilmissen, Dunsen, Deinsen, Marienhagen and Sehlde.
Greetings,
Monika (Moehring)
www.genealogiemoehring.npage.de