14 GinDEBOOK OF THE WESTEEIST UNITED STATES. 



i 



erous near the wagon-road bridge at Steels Crossing. They belong 

 to the pruicipal coal-bearing formation of Washington, presently to 

 be described, and are associated with lavas. At Steels Crossing the 

 raihoad enters the coal field of western Washington, the largest in 

 the State. The productive portions of the field, however, are miles 

 away, northeast and southeast of this point, about Newcastle and 



iamond and Franklin, W 



The field contains m 

 mined, in nlaces to 



The coal ranges from 

 mainlv subbituminous 



and bituminous. Coking coals occur at a number of localities and 

 are worked m the Wilkeson region. They are the only coals coked 

 commercially on the Pacific coast. 



The fossil plants that are associated with the coal and that repre- 

 sent the vegetation from which the coal was formed contrast strongly 

 with the plants of this region to-day. In the present forest conifers 

 are dominant in size and number, but in the forests of the Eocene 

 coal period conifers were few and palms and deciduous trees were 

 abundant. No palms now grow wild within a thousand miles of the 

 Puget Sound region, so the climate here during the coal period must 

 have been very unlike that of to-day. The coal-bearing rocks crop 

 out at intervals alons: the western base of the Cascade Range from 



the international boundary on the north to the Columbia on the 

 south. 



The railroad crosses Black River, the outlet of Ijake Washington, 



Black River Junction. 



iction, from which branch Imes lead to the Isew- 

 castle, Renton, and Black Diamond coal fields. 

 The mine at Renton is only 2 miles to the east 

 Elevation 39 feet. (^i^ft) of Black Rivcr Juuctiou. Two bcds are 



Seattle 10 miles. mined here. The thicker one is 2 feet 8 J inches 



thick and inclines orliips southeastward at an 

 angle of 12'^. The coal is subbituminous. 



From Seattle to Tacoma the railway follows a broad valley in 



drift which forms 



Th 



from Duwamish 



the melting of the ancient glacier as one of the intricate series of de- 

 pressions now occupied in part by Puget vSound. It was later partly 

 filled with silt, sand, and gravel by the mountain streams. White 

 River, which enters the valley on a low deposit of gravel and sand 

 which it has itself built up south of Auburn, separates on this sloping 

 deposit, or alluvial cone, into two streams- One, which retains the 



te River, flows northward into the Duwamish, and the 

 id Stuck River, turns to the south and joins the Puyallup. 



Wh 



This division of a stream 

 tells the 



gravel and sand into this old depression. The later floods 



