96 GEOLOGICAL SUliVEY OF THE TERRITORIES. 



more distinctly, and finally tlie whole graduates into a dark-drab clay. 

 At the bottom of the coal there is also a kind of mud shale. In the beds 

 above and below the coal are thousands of impressions of deciduous 

 leaves, as Foimlus, Platanus^ liUa, &c. Some of the layers of rocks, two 

 to four inches in thickness, are wholly composed of these leaves in a 

 good state of preservation, and so perfect are they that they could not 

 have been transported any great distance. 



This western country will eventually be one of the most important 

 coal-mining regions in America. 



The Union Pacific Eailroad Company has placed its coal interests in 

 charge of Mr. Thomas Wardell, an old English miner, and he is constantly 

 enployed in prospecting and opening mines the whole length of the 

 road. At Carbon he has erected six pretty cottages as residences for 

 the miners, and a number more are in process of building at Separation 

 and Point of Eocks, and other little mining villages will be built up. 

 All the apparatus for permanent and extended mining operations will 

 be gradually introduced. 



Nearly all the wood now along the line of the road has to be trans- 

 ported for a distance of 10 to 40 miles, and in two years from this time 

 most of it within a reasonable distance of the road will have been con- 

 sumed. The future success of this great thoroughfare is, therefore, 

 wholly dependent on the supply of this mineral fuel, and its imi)ortance 

 cannot be too highly estimated. 



From Saint Mary's to Eawliug's Springs, a distance of about 30 miles, 

 the railroad passes over rocks of Cretaceous age. No coal beds need be 

 sought for in the immediate vicinity of the railroad, although it is quite 

 possible that on the north side of the road isolated patches of Tertiary 

 containing coal may be found. The railroad, from a point about eight 

 miles east of Benton to Eawling's Springs, passes through one of the 

 most beautiful anticlinal valleys I have seen in the West. On either side 

 the rusty-gray sands and sandstones dip away from the line of the road 

 at an angle of 10 to 15 degrees. This anticlinal valley is most marked 

 near Fort Steele, at the crossing of the North Platte. About five miles 

 east of Fort Steele I made a careful examination of a railroad-cut through 

 a ridge of upheaval, which inclined about south or a little east of south. 

 We have exposed here, commencing at the bottom, 1st, gray fine- 

 grained sandstone, rather massive, and good for building purposes, and 

 easily worked, 80 feet thick, dip 25° ; 2d, a seam two feet thick, irregular, 

 black, indurated slaty clay, with layers of gypsum all through it ; then 

 two feet of arenaceous clay ; 3d, 10 feet of rusty-gray compact sand- 

 stone ; 4th, eight feet clay and hard arenaceous layers, very dark color, 

 passing up into harder layers, which split into thin laminse, the surfaces 

 of which are covered with bits of vegetable matter ; 5th, about 50 feet 

 of rusty yellowish-gray sandstone ; all these sandstones contain bits of 

 vegetable matter scattered through them; 6th, 100 to 150 feet of steel- 

 brown indurated clay, with some iron concretions ; the clay is mostly 

 nodular in form ; 7th, a dark-brown arenaceous mud rock, quite hard, 

 three feet. From bed fifth I obtained numerous species of marine shells, 

 among them a species of Ostrea and Inoceramns in great numbers. The 

 upper surfaces of the hard clay layers appeared as though crowded with 

 inipressions of sea-weeds or mud markings. 



In another railroad cutting, about four miles east of Eawling's Springs, 

 I obtained the same Inoceramns and a large species oi Ammonite. These 

 fossils are quite important as establishing the age of these rocks. 



At Eawling's Springs are some very interesting geological features. 

 At this locality the elevatory forces were exerted more powerfully than 



