Photo from the Tassajara History page - thanks ZMC director Carolyn Cavanaugh for sending it.
From A Brief History of Tassajara by Marilyn McDonald (Cuke Press 2018)
Marilyn used 1539 feet as the altitude of Tassajara surely because that’s the number on the geological survey marker embedded in sandstone at the steps to the old hotel. On January 19, 1981, the US Geological Survey entered 1637 feet as the official altitude in the Geographic Names Information System.