Mill "C" Complex, Sand-Sorting Building, South of Dee Bennet Road, near Illinois River, Ottawa, La Salle County, IL

Significance: The St. Peter sandstone anticline forms the bluffs and lies beneath the terraces of the Illinois River Valley west of Ottawa, Illinois. The anticline, and 100-200' thick, horizontal layer of loosely bonded sandstone covered by a thin layer of overburden, furnishes the raw material for silica sand processing. The anticline's thick seam, ease of extraction, exceptional purity, and uniformly high silica content make it an excellent source of sand for glass making, foundry molding, and sand blasting...
Survey number: HAER IL-24-A