Page 117. At New Ulm, in Brown county, are two flourishing potter’s establishments, owned by Messrs. Dauffenbach and Gieseke, and by John Steket (Stoeckert). At the former a blue clay "from the Cottonwood" is mixed with a similar blue clay
Page 118. obtained from the drift at New Ulm. The latter overlies a heavy stratum of waterwashed and stratified white sand. It is said to be necessary to mix these clays to obtain a material that will not crack in the kiln, that "from the Cottonwood" being much addicted to that fault. The same clay makes a red brick when harder burned. A white clay is also used by Dauffenbach and Gieseke for making fire-brick. Their kiln and fire-arch are built of brick of their own manufacture from this clay, and appear to stand well. This clay is obtained at some distance from New Ulm, at a point said to be known only to the proprietors. (The Geological and Natural History Survey of Minnesota, The First Annual Report, For The Year 1872, N. H. Winchell, Press Printing Company, St. Paul, 1873)
Fire Clay. From the Cretaceous, near New Ulm, Mr. Christian Daufenbach manufactures a good fire-brick. The bank from which he takes the clay is fifteen feet above the river. It is of light color, and when wet is plastic, but if dry it is hard and difficult to quarry, the use of powder becoming necessary. Horse powder is used for his machinery. He has three kilns. This fire-brick clay lies below a heavy stratum of white sand. (The Geological and Natural History Survey of Minnesota, The Second Annual Report, For The Year 1873, N. H. Winchell, St. Paul Press Company, St. Paul, 1874, Page 207)