THE GEEEN EIVEE COAL BASIF. 467 



The Coalville District. — The Mormon settlement of Coalville is 

 situated about five miles southeast from Echo City. From the mouth of 

 Echo Caiion the road follows up the east bank of the Weber River, which, 

 for the first mile and a half, occupies a broad, level bottom, eroded through 

 the strata of Tertiary sandstones and conglomerates. The high red and brown 

 bluffs which flank the river on either side, are very conspicuous features of 

 the landscape. Continuing southward, the valley widens to the average 

 breadth of a mile, and the upturned rocks of the coal series are seen rising 

 on either side of the river, underlying with a nonconformity of 11° the red 

 hills of the Tertiary. From this point for 16 miles the coal rocks are exposed 

 on either side of the Weber River, rising into the hills to a varying alti- 

 tude, rarely exceeding a thousand feet, where they lose themselves again 

 beneath the Tertiaries, which continue upward two or three thousand feet 

 higher. In other words, the river has carved a canon, first, through the level 

 Tertiary beds, and last, for a thousand to fifteen hundred feet into the soft, 

 upturned strata of the coal series. By referring to the map, Atlas-Plate I, 

 the Pacific railroad will be seen following Echo Canon in a direction about 

 northeast. Two miles to the south of that, a canon is seen to cut the Terti- 

 ary strata parallel with Echo, joining the Weber River half-way between 

 Echo City and Coalville. At the town of Coalville a third southwest stream 

 joins the Weber. All three of these parallel systems have eroded the Ter- 

 tiary and entered the coal series. Chalk Creek, as it is called, which enters 

 the river directly at Coalville, has exposed the coal series for 18 miles, and 

 in the tributaries which have worn ravines upon its northern bank are located 

 the groups of mines embraced in what is known as the Coalville District. 

 Directly south of the town, and in the right-angle formed by Chalk Creek 

 and the Weber River, is situated Sprague's mine. The vein of coal out- 

 cropped indistinctly upon the level flat and has been followed by a couple of 

 tunnels southward under a little rise of ground. In close conformity with 

 the rocks of the region the strike is north 28° east, magnetic. The strata 

 have a westerly dip of about 14°. The vein itself has an average width of 

 11 to 14 feet, resting directly upon the cream-colored sandstone and roofed 

 by thin strata of the same material, which, passing upward, alternate with 

 bands of shale and sand. A slight bending has taken place near the outcrop 



