43 U.S.C. § 38 : US Code - Section 38: Topographic surveys; marking elevations

Search 43 U.S.C. § 38 : US Code - Section 38: Topographic surveys; marking elevations

In making topographic surveys west of the ninety-fifth meridian
elevations above a base level located in each area under survey
shall be determined and marked on the ground by iron or stone posts
or permanent bench marks, at least two such posts or bench marks to
be established in each township, or equivalent area, except in the
forest-clad and mountain areas, where at least one shall be
established, and these shall be placed, whenever practicable, near
the township corners of the public-land surveys; and in the areas
east of the ninety-fifth meridian at least one such post or bench
mark shall be similarly established in each area equivalent to the
area of a township of the public land surveys.