106 STEVENSON— INTERRELATIONS OF FOSSIL FUELS. 



with several beds of dark shale and some seams of coal ; the lower 

 portion, about 370 feet, and without coal, is sandstone except 78 feet 

 of sandy shale at the top. Four coal seams were seen in one sec- 

 tion, three of them thick enough to be mined ; but the coal is very 

 dirty ; that from the best contains 20 to 24 per cent, of ash and the 

 washed coal, utilized in making coke, retains 21.71 per cent. This 

 Montana of Calvert rests on a mass of shale and sandstone con- 

 taining Colorado fossils throughout ; which makes probable that 

 basal member of the section may be equivalent to the shales of the 

 Lower Pierre and that the coal-bearing member may be at the Eagle 

 or Mesaverde horizon, there being Mesaverde fossils throughout. 

 The " Montana " beds underlie conformably the Livingston forma- 

 tion, a mass of andesitic material. Calvert found similar conditions 

 in the Livingston coal field farther north in the same county, except 

 that his Montana beds are thinner. There are not less than 3 seams 

 of coal, 2 to 20 feet thick ; but they vary rather abruptly in thickness 

 and the coal is of uncertain quality. Two samples from one mine 

 gave 8.77 and 17.5 per cent, of ash; analyses of samples from other 

 mines yielded 8.44, 10.92, 10.99, i4-9> 27.53 and 31.51 per cent, in 

 air-dried coal. Cross-bedded sandstones were noted by Calvert in 

 both fields. 



Newberry®^ noticed that coal near Bozeman, in the Livingston 

 field, contains a large quantity of yellow, translucent, almost amber- 

 like resin. Weed^" examined the same fields at an earlier date and 

 called especial attention to the uneven floor of the coal seams. This 

 as well as the occasional disappearance of the coal led him to believe 

 that the coal seams had been formed in depressions of the surface. 

 He found Unio in beds associated with the coal seams of the Electric 

 coal field. 



In Meagher County, north from Park, Stone recognized the 

 four formations. The Bearpaw shale, marine throughout, has no 

 coal ; the Judith River, brackish and fresh water, has some lenses 

 of coal, usually very thin and of short lateral extent ; when of work- 

 able thickness, their coal is apt to be dirty. The Claggett, marine 

 and brackish, appears to be without coal. The Eagle has coal, but 



s« J. S. Newberry, Ann. N. Y. Acad. Sci., Vol. 3, 1884, p. 245. 

 8' W. H. Weed, Bull. Gcol. Soc. Amcr.. Vol. 2, 1891, pp. 349-364. 



