Sebastian Keyser

http://user.xmission.com/~octa/DonnerParty/Rescuers.htm#Keyser

A native of Austria, Keyser was trapper who had gone overland to Oregon with Sutter in 1838 and later joined him at New Helvetia. In 1845 he settled on Bear River as a half-owner of William Johnson's ranch. The following year he married Elizabeth Rhoades, sister of John and Daniel; she left him for a while, but they were reunited. Keyser sold his interest in the ranch in 1849 and operated a ferry over the Cosumnes River, where he was drowned in 1850, leaving one child.