In Norway, the last name of the son of the father became "son" and the daughter of the father became "datter".
For example, in our family, Ole Ols had a son Ole, who then became Ole Olson. Ole Ols had a daughter, Marie who became Marie Olsdatter.
For more information on the Norwegian naming system, go to the following website:
Ole Sr and Mari Olson had 11 children, though as of this writing, I have only been able to track down 10:
Elizabeth, Sarah, Maria, Iverdine, Bertha, Rakel Marie, Ole Jr, Mary B, Bertel O, and Rasmus.
Elizabeth, Sarah, Ole Jr, Mary B, Bertel O and Rasmus have been documented moving to the United States, along with their parents, Ole Sr and Mari.
Maria died at the age of 3 in Norway. I have been unable to confirm whether Iverdine, Bertha and Rakel Marie left Norway. (For the record, Iverdine and Bertha were twins.)