Donaldson in Wisconsin

I'm trying to find any information on my Great-grandmother's mother's family. My grandmother gives her mother's mother's name as Betsy Margretta and that is all. The children are named Donaldson. My grandmother says there were 3 named Catherine Ann, Daniel and Laura. The exact date they were born (or even if they were born in Wisconsin or Norway) is unclear, but it seems to be between 1856-63. My grandmother says the father was a ship's captain, but there is no first name. I'm having a terrible time trying to find any records of them before 1878 (Laura marries in Wisconsin.) But there are three children the the Waukesha Reform school in 1870. One is named Kate, one Daniel and one Boyon (a girl). (Laura gives her name is Laura B.) It says they were all born in Norway. Something very bad must have happened for these children to end up in this situation. If anyone knows anything or has any guesses, I'd be happy to hear of them.