STEVEXSOX— INTERRELATIONS OF FOSSIL FUELS. 125 



farther south in the foothills the formation is thin. In the basal 

 700 feet, there is a ripple-marked sandstone as well as shales and 

 sandstones with impressions of rain drops. Sandstones and shales 

 are irregular throughout and clear evidence of contemporaneous 

 erosion was observ^ed at several localities. Some thin beds of con- 

 glomerate were seen but they are indefinite and are clearly local. 



Twenty-one coal seams were seen in a section of 2,760 feet, from 

 2 inches to 9 feet thick ; in another section of about 1,100 feet in the 

 upper part of the formation. 7 seams were seen, with total thick- 

 ness of about 26 feet, while in a third of nearly 1,300 feet, there 

 are 8 seams with total thickness of more than 52 feet, besides other 

 seams less than 3 feet thick. Comparison of the sections make clear 

 that the seams are lenticular. The coal throughout is bituminous 

 and, with rare exceptions, is coking. The quality is excellent, ash 

 and sulphur being low. 



^lalloch thinks that the shales, sandstones and conglomerates 

 are of fluviatile origin. Absence of roots in the floor of coal seams 

 leads him to suggest that these may have developed in bogs within 

 choked oxbows or on coastal plains. The quantity of coal decreases 

 rapidly eastward from the mountains. 



Some Chemical Features of Cretaceous Coals. 



No substance resembling the pyropissite of Sachsen has been 

 mentioned by any observer, the only allied material being that seen 

 'by Dunker in the Hannover region, which he thought might be 

 hatchettin. Resin of one sort or another occurs commonly ; it is 

 termed Bernstein, retinite, walchovite or simply resin by various 

 authors. It is in grains or in lumps several inches long in the Lower 

 Quader coals of Bohemia and Moravia ; at one locality in Hungary 

 it is so abundant as to give the local name to k coal seam ; there is 

 much in New Zealand ; in North America, resins are characteristic 

 features of coals in the Laramie, the Fox Hills and the Pierre as 

 well as in those of the Benton. The color is from honey yellow 

 to dark yellow and according to Thiessen is rather darker in the 

 Fox Hills coals of northern Colorado than in the Eocene coals of 

 the Dakotas. Resins appear to be wanting in bituminous coals of 



