180 STEVENSON— INTERRELATIONS OF THE FOSSIL FUELS. 



The dips in the Monte Diablo area reach 70 degrees ; the water in 

 the coal is always low, sometimes not more than 3 per cent. ; the ash 

 is from 4 to 18 per cent.; but everywhere the coal seems to be very 

 far from the bituminous grade. In southeastern Montana, the ash 

 varies from 15 to 25 per cent. 



The air-dried samples of Greenland coal, analyzed by Moss, as 

 already cited, resemble a good bituminous coal, but the coal is a 

 typical brown coal in all physical features. Miocene coals from 

 Trinidad were analyzed by Percy, who obtained 



In every case, the specimen for analysis was taken from the 

 outcrop ; all are attacked energetically by caustic potash. Experi- 

 ments in the Survey laboratory showed that No. IV cakes. Resins 

 appear' to be wanting. '^° 



A. S. McCreath's analyses of coal from the Miocene of Advent 

 Bay, Spitzbergen, gave for dififerent parts of the bed 



N. Dubois determined the ultimate composition of slack coal from 

 the lower part of the bed, thus : Water, 4.14 ; carbon, 67.88 ; hydrogen, 

 4.05; oxygen and nitrogen, 11.90; ash, 12.03, or about 83 per cent, 

 of carbon and 14 of oxygen in the pure coal. The notable features 



-°*5 G. P. Wall and J. G. Sawkins, " Trinidad," etc., pp. 123, 126. 



