Knudsen (Fosnes)/Nilsdatter

Hello! I'm now looking for information on Martinus Knudsen Fosnes b abt 1780 d 1860 married to Petrine Nilsdtr b abt 1780 d 1844. They had 8 children (4 I can find info on). As far as I can tell, most of them were born in Gloppen, Sogn Og Fjordane. Here is the info I have: Lasse Martinusen Fosnes - no info other than what my grandmother gave me. Nils Martinusen Fosnes - same as Lasse. Martinus Martinusen b abt 1809 Marthe Martinusdtr b abt 1815 Amund Martinusen b 29 aug 1819 d 29 aug 1819 Amund Martinusen b 13 aug 1820 d 2 oct 1884 (in Montevideo, Chippewa, Minnesota) Simon Peder Martinusen b 7 jul 1823 (I believe he died in Minnesota but I'm not sure) Rakkel Martinusdtr b 18 dec 1829. I think some of them came to the US in or around 1867. (This was according to a 1930 census for Amund Martinusen's son, Kristoffer (Christopher) who was born on 2 jul 1862 in Gloppen) According to a 1910 census, Christopher came to the US in 1866. So, it must be 1866 or 1867. He was a child, so his parents should have been the ones to bring him! I did look on Digitalarkivet and found the birth record for 3 of Amund's children and found them in the 1865 census for Norway. If anyone can find anything, I'd really appreciate it. Thanks!!