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.
[Sidenote: The Common Point, equidistant between Tacoma and Seattle.]
_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," 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.