the lignite was largely carried away by erosion previous to the advance of the ice, which in turn pushed off the remaining Laramie clay, substituting glacial till in its place. Possibly some of the coal was cut away from the surface of the seam at the same time. A shaft sunk a few rods further up the hill penetrates forty feet of drift and then discovers the seam of lignite which appears in the coulee, it having at this point a thickness of eight feet.

Mr Witz, the manager of the mine, will run his threshing engine to operate the mine during the winter and spring, using the shaft rather than the outcrops in the coulee, where the coal is more or less weathered. The following is an analysis of the dried - lignites from this opening:

The other mines of this area are situated on the north side of Dogden Butte. Mr. F. B. Mosteller has filed a coal claim in Township 150, Range 79, Section 2. The seam measures four feet at this opening. At the opening owned by Mr. Parks, two miles northwest of the Mosteller mine, the seam also has a thickness of four feet.

The James and Bently Mine.-When the James mine was visited, its operator, Mr. Bently, was actively engaged in stripping the overlying fifteen feet of boulder clay from a large area of the lignite. This mine shows the following section:

The

This mine is located just over the line of McHenry county, in Township 151, Range 79, Section 32. The seam outcrops for several rods along the coulee, and though it is but two or three feet above the creek level, it is well drained at the present time, as only a small quantity of water issues from the coal. mine has been worked for four years and about 2,000 tons of lignite removed. Not the least of the conveniences which the enterprising manager, Mr. Bently, has arranged is that of selecting a trail that follows low ground almost on a direct line

to Balfour, thus shortening the haul and furnishing a level road for customers. The analysis of the dried lignite from this mine. is as follows:

One other outcrop of coal was reported from this section, lying eight miles to the east, near water level in a coulee that drains to the sloughs north of the butte. Such an outcrop is not improbable, and is even to be expected from the level of the area intervening between the Dogden Butte mines and Balfour. This area includes a stretch of hilly ground, which, though drift covered, probably contains the lignite bearing Laramie series, lying at an elevation considerably above that assigned for the mines at Dogden Butte. The record of several wells of moderate depth in this area shows no lignite, but these wells all stop short at the water bearing gravel, thus failing to penetrate the deeper clays that might contain the lignite.

LIGNITE DEPOSITS OF MERCER COUNTY

Field work in Mercer county this summer was necessarily restricted to a small area, but statements obtained from reliable sources add materially to the data personally collected. The county will be studied carefully next summer, when it is proposed to follow the Knife river through the county from southwest to northeast, and to examine carefully the bluffs of the Missouri river which form its northern and part of its eastern boundary.

Lignite is distributed abundantly through Mercer county, and one of the first attempts to develop it on a large scale was made at Mannhaven, on the Missouri river. A number of years ago the Plenty mine, in Township 145, Range 84, Sections 5 and 9, near Mannhaven, was opened by eastern enterprise, and preparations were made to install an elaborate equipment. Flatboats were made to carry the lignite to points in South Dakota, and even farther down the river, but their construction being faulty they sank on their first trip, and the enterprise was abandoned. The coal seam at this mine is reported as thirteen feet thick with six inches of clay in the center. It is situated sixty feet above

the waters of the Missouri. The Mannhaven Mercantile Company owns a mine near Mannhaven, in Township 146, Range 84, Section 7. The seam here mined, which is visible along the river for a mile and a half, is five feet above summer water level at its southern end, while it touches the water farther north. Its thickness is seven feet and the quality of the coal is reported as good. The mine is directly on the river and is worked during each winter, the amount of lignite taken out annually amounting to about 1,000 tons. Above the lignite lies a sandy clay.

In Township 145, Range 87, Section 31, lignite in workable seams is said to outcrop frequently, good springs occurring with it in great abundance. In Township 145 Range 86, Section 32, eight feet of lignite outcrop on a coulee. A coal bank is opened up here, the lignite being obtained by removing from eight to nine feet of clay. From Township 145, Range 85, Section 33, three feet of lignite of a rather inferior quality are reported. Mr. W. H. Mann, the founder of Mannhaven, is authority for the occurrence of a twelve-foot seam in Township 144, Range 87, Section 29, near the banks of the Knife river, and for another of the same size which outcrops in Township 144, Range 85, one mile south of the town of Deapolis.

LIGNITE DEPOSITS OF OLIVER COUNTY

Opportunities for natural exposures of the abundant lignite seams of this county are given by the Missouri river on the eastern boundary, and by Square Butte creek, a tributary of the Mis souri, and branches of the Knife river. Most of the information at present available in regard to this county was furnished by Mr. W. H. Mann, of New Salem, whose standing in the community and long acquaintance with the county make his statements great value. The following seams are reported by him:

of

The county will be included in the field work of the State Geological Survey next summer, and work in this area promises to be very fruitful.