at DeGraff, Swift county, 300 M. were made in 1877, selling at $10 per M.; (The Geological and Natural History Survey of Minnesota, The Eighth Annual Report for the Year 1879, Submitted to the President of the University, Feb. 18, 1880, The Pioneer Press Company, St. Paul, MN, 1880, Page 120)
Bricks. At De Graff, a quarter of a mile west from the depot, 300,000 bricks were made in 1877. They were cream-colored and of good quality, selling at $10 per thousand. The soil was removed to the depth of six inches, and the next five feet were used, consisting of the lower part of the soil and yellow clay, which are free from gravel. A tract of several acres here seems to have a subsoil of this kind. (A Report on the Geological and Natural History Survey of Minnesota, 1882-1885, The Geology of Minnesota, Volume II, N. H. Winchell and Warren Upham, Pioneer Press Company, St. Paul, Minnesota, 1888, Page 219)