OK. Frederick Joaquin Foss is not your man. He was born 1828-1833 in Denmark and died in San Francisco February 25, 1874, a native of Denmark.
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from
https://www.familysearch.org/wiki/en/How_to_Find_California_Death_Records"Before 1905, some counties in California kept death records."
some not all. So the factor isn't the possible lawlessness of the area, it's just that most places weren't keeping records. True of most of the US also until the early 1900's.
Familysearch pointed to 2 databases for deaths before 1905, one at familysearch and one at ancestry. I didn't find Frederick in either. I tried the front page of both sites, looking in California from 1870 to 1999, and still didn't find him.
There is still the possibility that he died elsewhere in the US or Canada, there are a few men born 1845 - 1855 on the US records. You'd probably have to weed them out one at a time by working backward to see if they lived their lives in the locality in which they died.
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at ancestry.com: San Francisco Passenger Lists arriving 1857 in California
no Foss found.
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that 1870 census tells you a few other things. the area of Salt Point they lived in, Samuel owned land and had money, and neither appear to be citizens. There is a column near the far right that asks that question:
1870 Timber Cove Post Office, Salt Point, Sonoma CA page 12, 28 July 1870
Frederick Foss, 21, rancher, born in England, parents of foreign birth, male citizen column not checked, no Real Estate or Personal Estate
1870 Timber Cove Post Office, Salt Point, Sonoma CA page 18, 28 July 1870
Samuel B Foss, 30, teamster, Real Estate: $500, Personal Estate: $200, born in England, parents of foreign birth, male citizen column not checked
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from
https://www.archives.gov/research/naturalization/naturalization.html1790 to 1922 (or later I forget), path to citizenship:
2 years residence: can file declaration of intention
3 years later: can petition for naturalization
if granted, certificate of citizenship issued
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so you can probably toss out the story that Samuel voted for Abe Lincoln. he still could have been a campaign worker though
. and I haven't googled to see if Lincoln made any campaign appearances in California.
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