|Object Name||microfilm aperture card systems|
|Scope & Content||
microfilm aperture card systems
REMARKS:Aperture cards prepared by Percy J.C. Brown, a Bureau of Land Management employee who researched original locations of segments of the Oregon Trail. This set of cards reprints various plat maps for Oregon Trail locations.
|Creator||Percy J.C. Brown|
|Title||Aperture cards of various survey plat maps|
|Collection||ARCHIVES AND MANUSCRIPTS|