When a surveyor needs an elevation, he goes to the nearest “bench mark”. This is typically a brass disk in concrete, although other solid objects are used. Each bench mark has a known elevation, already established on it. So, the surveyor can start at the bench mark, and transfer the elevation to his/her job site. This bench mark is stamped “HERTEL 22” and the elevation of the top of the brass disk is 167.63 feet (above sea level).
This cache is located in the Southeast one-quarter of section 25, 1 Township North of the Willamette Baseline and 3 Ranges West of the Willamette Meridian.
The Willamette Baseline was established running east to the Idaho border and west to the Pacific Ocean from the Willamette Stone, located in the Willamette Stone State Park. From these surveyed lines, the lands of the Northwest were divided into townships six miles square beginning at the Willamette Baseline and numbering north or south and given a range beginning at The Willamette Meridian numbering east and west. Each full township is divided into 36 sections of land 1 mile square which are numbered starting at the northeast corner of each.
The Willamette Stone is the initial point of the townships defining the grid system. The first marker, a red Cedar stake, was placed on the site in 1851 by John B. Preston, the first Surveyor General of Oregon, who was appointed by President Millard Fillmore to create a system for surveying land in the territory. The location was chosen such that the base line would not cross the Columbia River and the meridian would lie west of Vancouver Lake. The grid system was an extension of the system used in the Northwest Territory proposed by Thomas Jefferson.