Web site for “Mother Orchard Project” http://civileats.com/2014/09/08/the-mother-orchard-project-a-gold-rush-of-heirloom-fruit/

Bobby, On you tip I checked heirloom pears. I found one, Beurre Clairgeau that is same as ours in the picture. The picture was on a web site for a group that has found fruit trees planted along the paths the miners took to California for the gold rush and they are propagating them. We bought our old farm house over 40 years ago and the tree was big, mature and producing then. The house is over 100 years old. We think tree is 70 or more years old. Difficult to pick and ripen correctly. We have tried dark/light warm/cool/bananas and apples. About 30% success.

Have you searched heirloom pears? Smoked Salmon Belles may be a possibility. Approximately how old is the tree? That may help to narrow your search.