182 STEVENSON— INTERRELATIONS OF FOSSIL FUELS. 



lowest percentage of carbon in either county is barely 73 ; usually it 

 is somewhat more than 76 per cent. These coals are high in water 

 but not in ash. They are classed as subbituminous and are not held 

 in high esteem as better fuel from the Pierre is readily accessible. ^^* 

 The Pierre coals. These attain great importance in the San 

 Juan, Uinta and Green River Basins as well as in portions of 

 Alberta in Canada. There are few localities whence coal, positively 

 recognized as Lower Pierre, has been taken for official analysis. 

 Probably the Hagan coal of Sandoval County in New Mexico be- 

 longs here, but the only available analysis is proximate. The Upper 

 Pierre or the Lewis and the Bearpaw shales have no coal deserving 

 consideration. The Middle Pierre or Mesaverde, as originally de- 

 fined, is the productive formation. Its coals are mined in the Cerillos 

 coal field, where all grades from bituminous to anthracite are ob- 

 tained ; and in various parts of the San Juan Basin. Of the analyses 

 given here, L and IL are from the Cerillos field, II L and IV. are 

 from the southern part of the San Juan Basin, V., VI. and VII. are 

 from the northern part. 



1.6153. 

 II. 6154. 



III. 1307. 



IV. 1278. 

 V. 5761. 



VI. 2I2I. 



VII. 537D 



1-34 

 1.25 

 X.3S 

 1.28 

 1.71 

 1.70 

 1. 65 



The sample III. consisted of slack and VII. represented the run-of- 

 mine. II. and VII. yield a high grade coke. The anthracite of 

 Cerillos is believed to be due to a sheet of andesite overlying the 

 seam. 



The Mesaverde coals of the Uinta Basin are in two groups, sepa- 

 rated by a thick sandstone. The upper group, the Paonia shales, 

 has many coal beds of which one or more may be workable at a given 

 locality ; the lower group, Bowie shale, contains important seams. 

 In the southeastern part of this basin, the Paonia and Bowie cannot 



138 Bull. 22, pp. 137, 138, 69, 58, 59, 54, 55, 82 for Colorado-New Mexico; 

 pp. 310, 319 for Wyoming. 



