For the chanties from the 1850's, I need to add this one (again), from Gibb. It is in CALIFORNIA AND OREGON, OR, SIGHTS IN THE GOLD REGION, AND SCENES BY THE WAY, by Theodore Taylor Johnson & Samuel Royal Thurston (1850). It contains a verse from "A Hundred Years Ago", dated Sunday morning, 25th of March, probably 1849, departing San Blas. Here is Gibb's post, followed by the link:

thread.cfm?threadid=126347&messages=526#2866916

http://books.google.com/books?id=6G9HAAAAIAAJ&pg=PA88&dq=%22The+Oregons+a+jolly+crew,+O,+yes,+O!&lr==3#v=onepage&q&f=false