The Fresno Scraper is a machine pulled by horses used for constructing irrigation canals and ditches.  Invented  in 1882 & manufactured in Fresno by James Porteous,  the scrapper was in high demand by farmers.  A precursor to the bulldozer, larger versions of the Fresno  Scraper were used by  the Army Corps of Engineers in building the Panama Canal.

Fresno Scraper at Heritage Center
Custom Heavy Duty Fresno Scraper at Heritage Center
Sketch of a Fresno Scraper
Note the Fresno Scraper to the right of the horse team

For more information see the Wikipedia article.

1979.009.013 Scraper, Earth