Page:History of Stearns County, Minnesota; volume 1.pdf/30

 shafts were dug near this place in the hope of discovering workable lignite, by Theodore Bock. One of these went twenty-five feet, finding a lignitic layer six inches thick at thirteen feet, enclosed in blue clay, which, by boring twenty-five feet below the bottom of the shaft, was found to reach a depth of fifty feet, containing pyrite in some portions but no other lignitic seam. The other two shafts, forty and thirty feet deep, were wholly in drift. Eames referred this "coal" to the Cretaceous age, and rightly discouraged further mining for it, stating that his survey of the lignite-bearing starts on the Sauk and Cottonwood rivers "has demonstrated the fact that the state contains no outerop of coal of value, in so far as the counties examined and points coming under observation are concerned."

Repeated fruitless observations for lignite have been made, however, by shafts in the Cretaceous beds on the southwest side of the Sauk river in the N. W. ¼ of section 23, Munson, a fourth to a half of a mile west of Richmond. In 1871, at a point some thirty rods west of the bridge and less than a hundred feet from the river, a shaft was dug andb ored to the depth of 120 feet. Its top is about 25 feet above the river. Black clay or shale with some lignite, which is seen here in the river's bank, was penetrated and found to be three feet thick. A drift dug in 1865, starting about twenty-five feet farther northwest and following the lignitic layer sixty feet, found it to dip westward about four feet in this distance. It was said to contain "a seam of lignite four inches thick, which kept increasing in thickness, but remained impure and was considerably mixed with shale." Above and below the lignitic stratum is bluish gray clay or shale containing rarely crystals of selenite (gypsum) up to three inches long. J. H. Kloos found in the material brought up from the shaft "several fragments of shale containing scales of cycloid fishes, which had been met with near the surface." At a depth of 112 feet, according to Kloos, this boring reached "a hard rock, which proved to be granite. It was drilled for eight feet, and the fragments brought to light by the pump consist of feldspar, quartz and pyrites, such as are found in varieties of pegmatite or graphic granite, which I also found at the nearest outcropping ridges of the crystalline rocks." Nearly a quarter of a mile west from this place and about 75 feet above the river, another shaft was dug and bored in 1871 to the depth of 180 feet. This passed through a considerable thickness of drift, below which were blue, white and yellowish plastic clays, and shale. No more lignite was encountered than in the drift and the other shaft.

Again, in 1880 and 1881, the Richmond mining company claimed to have bored to the depth of 125 feet at a point only ten feet distant from the shaft and broing first described, close to the river. The only lignite found is the layer seen above the river-level; blue clay, with thin laminae of white and yellow clay, lies above the lignite; and bluish or greenish gray clay and shale extend below to the bottom of this section. No sand nor gravel, nor any hard rock, were encountered. In respect to these explorations, it must be added that it seems certain that no valuable deposits of lignite exist in this region, nor indeed in any portion of this state.

The only fossils known to have been found in these shafts are the fish- 