Thorack Surname Looking for History Info Connections OR

My great grandmother's name was Anna THORACK. She was born in approx. 1860's. She was married to Johann ANDRZCKI (Born in 1866). They had 7 children. They were: Ellie, Francisca, Helena, Anna, Alois, Hans and Antonia. Antonia was my grandmother. They were a coal mining family originally coming from Poland to Germany in the late 1800's. Before Poland I don't know where they came from, possibly a Slavik country.

I am having a hard time finding any information on the surname THORACK. I have even contacted William Hoffman, the Polish name expert and he has not heard of it before. I have not found it in any databases either.

Any information would be helpful. Is your last name THORACK?

Thanks so much, Moka