Age: ?
Fourth Relief

       Joseph Sels’ surname is spelled variously as Sells, Sel, and Sell; he sometimes went by the surname Foster; and is also referred to as “Jack the Sailor.” Other than that he was a sailor, next to nothing is known about him. Like Coffeemeyer, he visited Sutter’s Fort several times between May 1847 and March 1848, but after that nothing further appears.

Sources:

New Light on the Donner Party, Kristin Johnson

Ordeal By Hunger, George Stewart