MAP OF WILKESON COALFIELD

These coal-beds stand at high angles (fifty degrees and upwards), and dip in different directions. At Carbonado, there are four seams in pairs, separated by Carbon River, two of which dip to the south, and two to the north. At the South Prairie mines there are two seams, one of which dips to the east, and the other to the west. At Wilkeson there are three seams, all of which dip to the west. Mr. Willis interprets this coal-field as being a dome-like anticlinal, with compressed and crumpled sides, whose major axis runs nearly north and south. The Wilkeson and South Prairie mines are on the line of the major axis, whilst the Carbonado mines are in a group of subordinate short folds lying south of the main line. The anticline extends to Nisqually River, and shows two other coal areas south of Carbon River, the coal of which is said to resemble the Wilkeson coal.

The Carbon River coal-field first having been almost engulphed by volcanic uplifts and overflows, and almost buried by glacial drift, is now visible only in narrow strips along creeks, and at intervals along the Carbon River.

Owing probably to the heating of its beds, we find in this little field the coal which stands highest in reputation for coking and heating qualities. There are some differences in the coal at the three mines. That at South Prairie was sold chiefly for making gas. The best of the Wilkeson coal is made into coke, and is in demand beyond the supply. The price is $7.00 a ton at the ovens. The entire product of the Carbonado mines is said to go to the Central Pacific Railway. It is impossible to say what may be under the Drift; but, to all appearance, the amount of coal here is not large, and the beds are sadly faulted, and pitch deep into the ground.

b. The Green River Group.—I include in this group the Black Diamond and Franklin collieries, the Kirke or Moss Bay Company mines, and the Sugar Loaf Mountain beds. This, as well as the Carbon River field, is nearly equidistant from Tacoma and Seattle, being about thirty miles in a right line from each place. The Carbon River basin is geologically associated with Mount Ranier; the Green River basin with the outliers or foot ridges of the Cascade Mountains. The latter are much more approachable than the former. At the east edge of this field, the Northern Pacific Railroad emerges from the Cascade Mountains, having come down the cañon of Green River. This point is known as "The Common Point,"The Common Point, equidistant between Tacoma and Seattle. because the cities of Tacoma and Seattle are about equally distant, and the routes afford equally good grades from this point.

The narrow gauge road from Seattle now comes to the Franklin mines, and by continuing it a few miles to connect with the Northern Pacific there would be railroad connection to Seattle as well as to Tacoma. The river here cuts through the Coal Measures, leaving the less valuable part of the field on the south side. The area of this field is roughly estimated at fifty square miles. It contains all, or nearly all, the grades of coal from lignite to bituminous; the variety of coal depending upon the degree of local disturbance. As a rule, so long as the coal is not crushed, the more pitched and flexed the rocks, the better the coal; which fact indemnifies the miner for extra expense in mining. Here, the tendency is for the seams to become steeper and more broken from west to east; i.e., as they approach the foot-hills of the Cascade Mountains. The strata in Lizard Mountain on the south side, however, form an exception. Here the strata are nearly horizontal.

Franklin and Black Diamond mines.The Franklin mines are on the north bank of Green River and at the south edge of what has been known as the McKay basin, and the Black Diamond mines are on, or near, the north edge of the same small, oval synclinal basin. From this basin the dips become steeper toward the mountain, where Kirke's beds stand at a high angle. On the west edge of the Green River basin, say a mile west of Franklin, there is an outcrop of lignite. The coal of the Franklin and Black Diamond mines is bituminous lignite. The Kirke coal, or at least part of it, as judged by the eye, may be called bituminous coal, though not so much deoxidized as the Wilkeson. The coals mined in this basin are firm, black and shiny; they burn freely, and make but little dust. They have not, however, so far as tested, the heating power or coking qualities of the Wilkeson coal. Two seams are worked at Franklin, and three at Black Diamond. All of the seams worked are above four feet. A number of volcanic dikes and flows are found in and around this basin.The Kirke or Moss Bay Company (English) mines.

The Kirke or Moss Bay Company mines are six miles east of Franklin, and within a mile of Green River. They lie against the mountain. The strike of the mountain is northwest. The coal beds dip toward the mountain at a high angle. There are five seams of from five to fifteen feet in thickness; one of them (No. 2) may be said to be over forty-seven feet in thickness, though not all good coal, as the details given below will show. The top of the outcrops above sea-level are as follows:

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