Hi, I found Jason and Florence Clark in 1930 living in Camas, Clark Co., WA. J B, b. MO, 36 yrs old, pipe fitter paper mill; Florence, b. KS, 31; David, b. NE, 12; Dorothy, b. OR, 9; Betty, b. WA, 7; James, b. WA, 5; Robert, b. WA, 4 and Walter b. WA 1 5/12ths.
I started to look up the children but there are too many people listed with the same names, Clark being a common surname.
I suggest that you look up the obituaries for Jason and Florence and find where each child lived last. That will narrow your search. A Jason B. Clark d. 3 May 1946, Clark Co., b. abt. 1892 per death cert #95. Source: WA Death Index.
You can contact the Secretary of State, http://www.secstate.wa.gov/library/ask.aspxhttp://www.secstate.wa.gov/library/ask.aspx for a copy of his obituary. They will search the newspaper microfilm for 30 minutes at no charge & reply with what they find.
Florence is much more challenging but I've listed the closest matches.
Florence Clark, d. 23 Feb 1981, Kirkland, King Co., b. abt. 1899 per death cert #005469. Source WA Death Index.
A Florence Clark, b. 1 July 1898, d. Feb 1980, Olympia, Thurston Co. Soc. Sec. # assigned before 1951. Source: Social Security death Index which anyone can access at no charge.
A Florence Clark, b. 25 Oct 1900 d. March 1981, Last Residence-Prosser, Benton Co., WA; Last Benefit=Sunnyside, yakima co. Soc. Sec. # assigned in CA before 1951. Source: SSDI.
A Florence Clark, Last Residence=Seattle (more probably where last benefit check mailed to), b. 20 May 1897, d. Sept. 1983. Soc. Sec. # assigned WA before 1951. Source: SSDI.
A Florence M. Clark, Last Residence=Seattle (more probably where last benefit check mailed to), b, 15 Oct 1897, d. 15 Aug 1990. Soc. Sec. # assigned WA in 1966. Source: SSDI. Successful Hunting!