Title supplied by cataloger based on information from sheet labels. Images are photoreductions of mosaics created from original aerial photographs. Designating symbol SX; form of individual image numbering: SX-1-[number], SX-2-[number], SX-3-[number], or SX-4-[number]."Date of completion 08-14-37" Flown by Gatschet Aerial Surveys, Des Moines, Iowa."Approximate scale, 1:20,000" [refers to individual images from which mosaic was made]. Library's copy 2 consists of photographic negatives (4 x 5 in.) corresponding to each of the images in its copy 1. Contact the Map Collection at The University of Iowa Libraries: http://www.lib.uiowa.edu/maps/contact/