STEVENSON— INTERRELATIONS OF THE FOSSIL FUELS. 157 



cannel, is so soft and tough that it can be cut with a knife. It is 

 free from foreign matter except at the bottom; occasioiiall}" a thin 

 carbonaceous mud, with slender stems as jet-hke fragments covers 

 the coal and a thin xyloid bench was seen midway in the bed. The 

 coal has high volatile, high illuminating power, high heating effici- 

 ency and gives copious yield of oil when distilled — the best yields 38 

 gallons per ton. 



Thiessen,--" in discussing this Lester material, says that it con- 

 sists of vegetable debris from a herbaceous flora, but contains bits 

 of angiospermous and gymnospermous w'ood, showing that a wood- 

 flora existed. Everything is so well disintegrated and decomposed 

 that very little is recognizable except the most resistant parts of 

 plants. Exines of spores and pollen grains, resins and an undeter- 

 mined waxy or resinous substance are conspicuous. The interstices 

 are filled with more finely macerated parts of those constituents. 

 Spores of fungi are present but are not abundant. The spore exines 

 are mostly those of ferns, there being few from lycopods, while the 

 pollen is both angiospermous and gymnospermous. Spores and 

 pollen grains make up about 30 per cent, of the mass and are associ- 

 ated with abundance of cuticles. The resinous bodies are of two 

 kinds, one, the lighter in color, is the more refractive and is paraffin- 

 like in consistency; the other is less abundant and less refractive. 



Eocene coals of the Rocky Mountains and adjacent areas are 

 especially important w^ithin the states of Utah, Wyoming, Montana 

 and North Dakota, where mining operations have been extensive at 

 many places. The citations which follow are mostly from the more 

 recent publications, as those of earlier date were made when oppor- 

 tunities for observation were not so good and dependence had to be 

 almost wholly on natural exposures. 



In one area within Utah, Richardson--^ found the coal between 

 beds of freshwater limestone, black bituminous, containing abun- 

 dantly the crushed shells of Sphccrinm and Physa. One bed is 36 

 feet thick, with 4 partings, of which the thickest is but two inches 

 and a half. The rocks are faulted and the dip is from 10 to 15: 



220 j^_ Thiessen, " Microscopic Study of Coal," the same, pp. 232-238. 

 --^ G. B. Richardson, " Coal in Sanpete County, Utah," U. S. Geol. Sur- 

 very, Bull. 285, 1906, pp. 281. 



