588 TH15 GEOLOGY OF MINNESOTA. 



[Fire-bricks. Poltcry. Paint. 



modified drift, situated near the top of the bluff of Redwood river, on its west side, about thirty 

 rods north of Cook & Co.'s mill, and nearly 50 feet above their mill-pond. The section here is 

 black soil, 2 feet, gradually becoming yellow in the next 2 or 3 feet; whence, compact yellow clay 

 extends to 9 feet below the surface, divided by darker partings into layers from four inches to 

 eight inches or a foot in thickness, which dip 2 or 3 E. These layers are distinctly continuous 

 along the whole extent of the excavation, about four rods. They are probably the depositions of 

 successive years; the finer, dark partings being the sediments of the season of low water; while the 

 great mass of each layer was made by high floods, with stronger currents and bearing more 

 abundant detritus, supplied from the melting ice-sheet during the warm portion of the year. 

 Below the depth of 8 or 9 feet the clay changes to yellowish sand, obliquely bedded in layers 

 from a quarter of an inch to one inch thick, separated by harder films of iron rust. Too much 

 sand was mixed with the clay in this brick-making, so that the bricks were somewhat deficient 

 in hardness and durability; but the clay seems to be excellent for this use. 



Fire-bricks. From Cretaceous beds on the Cottonwood river, good fire-bricks have been 

 made by Christian Dauffenbach, by William Winkelmann, and by John Stoeckert, at New Ulm. 

 The characters of the deposits used, and in what proportion, have been stated already in the 

 description of the section in which they occur (page 574). 



Pottery. Cretaceous clay, also obtained from the bluffs of the Cottonwood river, a few miles 

 farther west, as described on page 573, has been used in New Ulm by the same Messrs. Dauffen- 

 bach, Wiukelmann, and Stoeekert, potters. In 1879 and 1880, the two former had given up the 

 manufacture both of fire-bricks and pottery; but these lines of business are still carried on by 

 Mr. Stoeekert, his products being some $2000 worth yearly. 



Mineral paint. -A good and durable paint was manufactured in 1868 or 1869 from ferrugi- 

 nous portions of the kaolinized gneiss and granite mentioned in the vicinity of Redwood Falls. 

 The material thus used was obtained from the northwest or left bank of the Redwood river in its 

 gorge, about a mile north of Redwood Falls, in the N. J of the N. E. J of section 36, Delhi. Of 

 this business Prof. Winchell wrote in his second annual report: "At Redwood Falls the kaolin 

 which has resulted from the decomposition of the granitic rock, has become stained with iron, and 

 has a brownish or greenish-brown color. It contains, generally, some silica. From this stained 

 kaolin a good mineral paint has been manufactured. Messrs. Grant and Brusseau commenced the 

 enterprise, and carried it far enough to demonstrate the quality of the product. The manufac- 

 tured article is said to have been equal to that of Brandon, Vt.. but the cost was so great that, 

 after transportation to St. Paul, it could not be offered in the market so cheaply as the Brandon 

 paint. Their process was very simple. The raw material was obtained from the banks of the 

 Redwood river, and was of a rusty-brown color, having also a greenish tinge. It was broken or 

 crushed to the fineness of corn or wheat. It was then dried in a large pan placed over a fire, and 

 ground by water-power, between two burr-stones. In that condition it was ready for use by 



simply mixing with boiled or raw linseed oil The color produced was a reddish 



umber. By making some selections various lighter shades, of the same general character, were 

 produced. It had a heavy sediment, consisting probably of iron and silica. The quality of the 

 paint is said to have been superior to that from Ohio, and fully equal to that from Brandon, Vt. 

 The surface of the wood painted becomes hardened and glazed, but remains smooth." 



ABORIGINAL EARTHWORKS. 



The only aboriginal mound observed or learned of by inquiries in Brown and Redwood 

 counties, is situated a little more than a mile northeast from Redwood Falls, being on the high 

 prairie, about ten rods northwest from the road and twenty-five rods south from the edge of the 

 southwest bluff of the Minnesota valley. It has the usual circular, dome-like form, and is six feet 

 high. 



