Hi Christine, I found Ruth listed in the 1910 Watertown Ward 1, Codington Co., SD Census with her family. This Census says she was a Step-dau but George and Marie were marked as 1st marriage. Maybe George eventually adopted Ruth?
I didn't find her in any 1930 Census.
However she and her family are listed on the Anderson Family Tree on Ancestry.com. I've asked the owner to contact you. If they don't and you don't have access to Ancestry, you can sign up for free fourteen-day trial. Just be sure to cancel on day 13.
Ray Fred Marks b. abt. 1902, Idaho married Ruth Ellis 1928-1930 in Jackson Co., OR. Go to Rogue Valley Genealogy Society, rvgslibrary.org, marriage, Jean Ellis or Ray Marks. You can order their marriage license from the society.
According to the Anderson Family Tree and Oregon death index, Ray died 7 November 1956 in Jackson, Jacksonville Co., OR. Also shows that Ray and Ruth had no children.
I'd ask a volunteer to copy his obituary. You can find a volunteer at Random Acts Genealogical Kindness. Go to raogk.org, read guidelines, choose Oregon, choose Jackson Co. and choose one volunteer.
OR contact RVGS at address above.
On the Anderson Family Tree for Jean it says Unknown Father. Ruth might have married before Ray or Jean's father wasn't involved in her life. Jean was born abt. 1930 Jackson Co., OR. She died 2 July 2007 in Oahu, Hawaii.
I'd request a copy of her obituary too.
Then Jean married a Macklin Robinson and they had no children. I'd go to the Rogue Valley Gen. Soc. and see if they show Jean's marriage to Robinson. Successful Searching!