the north furnishes a most effective illustration of the nature of many of the lignite beds. The lignite throughout the seam appeared to be of good quality, with the exception of the upper two feet, which were rather soft. An analysis of dried material taken from four points at different elevations in the south end of the exposure gave the following results: Ash ..... Volatile matter 37.59 55.90 6.51 100.00 In one small area the seam is wholly burned out. On account of its position, great quantities of lignite can be obtained with very little stripping. Lignite on the Little Missouri Near the 777 Ranch.-Some very fine lignite seams outcrop at this point, which is some miles south of Yule. Rising directly from the water's edge at one point, the banks of Laramie clay and coal reach a.height of 110 feet, which is the level of the second terrace, shown in figure 13. In the hills back of this terrace the surfaces are concealed and a section in height equal to that at Medora could not be obtained. Lignite seams probably exist above those noted. The section shown was as follows: 8. Clay 20 7. Lignite 3 6. Clay 10 5. Lignite, soft 3 4. Clay 3. Lignite, good 5 2. Clay Fig. 6. Section thirty miles south of Medora at the 777 ranch, showing lignite seams. 1. Lignite, good, more Water level. This section is illustrated in figure 6. The lowest seam extended below water level, and its thickness could not be determined. It is shown in plate XV, where it extends from the water to the end of the hammer above the climber without a break. The other seams in the section are barely shown in the distant bluffs. The lignite from the lower seam is highly esteemed by the neighboring ranches, and appears to be unusually firm. An analysis of dried material taken from a somewhat weathered surface gave the following result : Volatile matter 34.55 43.47 21.98 100.00 Lignite at Yule.-Two and three seams are exposed in the bank of the Little Missouri both north and south of Yule, one of them of good quality. The lower seam found farther up the river and described in the preceding paragraph was not seen, but conditions were not favorable for an outcrop close to the water. Lignite in Black Butte.-This imposing butte, probably equal in elevation to Sentinel butte, is situated not far from Township 134, Range 101, about forty miles south of Medora. Like Sentinel butte it is capped with a heavy sandstone stratum. Two lignite seams are reported as outcropping in its sides, one of them, said to be six feet thick, being mined to some extent. At the Gamble ranch, three miles west of the butte, a fine spring was seen flowing from a lignite seam, the thickness of which was not known. The quality of the coal appeared good, and it was but a short distance beneath the surface. vey. LIGNITE OF MCLEAN COUNTY F. A. WILDER AND L. H. WOOD For convenience in description, the lignite of McLean county will be reported in connection with six centers: Coal Harbor, Fort Stevenson, Coal lake, Washburn, Dogden Butte and HarAll of these centers were visited during the past summer, the last two by Mr. L. H. Wood, who has described them for this report. Lignite is by no means restricted to these centers, but development work has been carried on about them to some extent, and data could be obtained without too great an outlay of time. The county will well repay more exhaustive study. Lignite About Coal Harbor.-Coal Harbor is situated in the western part of the county, near the Missouri river. The lignite deposits in its vicinity have long been known, and early attempts were made to exploit them. Naturally the first exposures recognized were those along the Missouri river. In the bluffs near Coal Harbor, the following section occurs: FEET 70 INCHES Clay Lignite Clay Lignite Clay 6 80 4 1 7 Lignite The lowest seam is 220 feet below prairie level, and thirty feet above the water of the river. Lignite outcrops also along two creeks in this vicinity. In Township 147, Range 84, Section 24, in a coulee forty-five feet below the upland level, a lignite seam was visited, said. to be eleven feet thick, though but seven feet could be seen at the time, the lower portion of the seam being covered with recent wash. As now exposed the lignite is covered directly by glacial drift, though Laramie clays will doubtless appear above it as the stripping is carried farther back into the bank. A twelve-inch clay seam occurs in the middle of the lignite. A small spring flows from its base. This seam is illustrated in plate XVI. As reported by Mr. Geo. R. Robinson, of Coal Harbor, eight and one-half feet of lignite at a depth of 108 feet were passed through in digging a well on Township 146, Range 83, Section 6; while on the same section, and starting from practically the same upland level, a well reaching a depth of 126 feet encountered no lignite. While the lignite beds often diminish in thickness rapidly, it does not seem probable that a scam of this size would thin out so quickly. In the report given of the occurrence the glacial drift and Laramie clays were not distinguished; and the phenomenon may be explained by preglacial erosion. In Township 147, Range 83, Section 30, seven feet of lignite are reported as occurring in a well sixty-eight feet below the surface. Lignite About Fort Stevenson.-For many years lignite was mined on the old Fort Stevenson reservation for use at the fort and the Indian school formerly located there. The exact location of the mine was in Township 148, Range 85, Section 35, southwest one-half. A seam said to be fourteen feet thick was mined by stripping. When seen last summer, the lower part of the excavation had filled in and only the upper two feet of lignite were visible. This mine is situated back of the broad, low terrace of the Missouri river, and about thirty feet above it. Higher up in the bluffs other lignite seams occasionally outcrop, the best exposures seen occurring half a mile east of the Fort Stevenson mine. The section here given was: The seam worked at the Fort Stevenson mine may be found twenty or thirty feet below the lowest number of this series. Springs of considerable size issue from the lignite at the Fort Stevenson mine. Conditions for drainage, however, are good, the seam lying considerably above the river flat. Lignite About Coal Lake.-There are large quantities of lignite exposed along Coal lake, formerly known as Buffalo lake, and the creek that drains it. Exposures are common in Townships 145 and 146, Ranges 80 and 81. Turtle creek was followed north from Washburn, and along its banks a number of exposures were seen. The seams generally reached a thickness of five feet. Throughout the valley the lignite is accompanied by springs, some of them of considerable size. In Township 145, Range 80, Section 29, a seam more than six feet thick was seen, the lower four feet apparently of good quality, while the top was soft. Considerable lignite is obtained from this point by stripping, the output last year being about 1,000 tons. The outcrop is about seventy-five feet below the upland level. In Township 146, Range 81, Section 13, on the east side of Coal lake, a new bank has been opened, showing three or four feet of coal. One-half mile further down the coulee on which this seam occurs is the "Little Coal Lake" mine. Though no coal could be seen where the bank was visited, a large amount of work had evidently been done during the preceding winter. of stripping now necessary is twenty-five feet, and further development can best be carried on by drifting. amount The amount of lignite exposed at the Coal Lake mine, in Township 146, Range 82, Sections 22 and 23, when visited in September, 1902, was nine feet. The lower portion of the seam was plainly concealed by wash from the slope, and the reported thickness of fifteen feet doubtless exists. The upper two feet are very |