Coal Bed of the Lance Formation. 



301 



carbonaceous sandstone. In the mass there is little lamination, 

 which distinguishes it at once from ordinary carbonaceous 

 shale. It is generally mixed with a certain amount of car- 

 bonaceous material, and contains plant impressions. Not 

 uncommonly the roots and plant stems are in place and are 

 perpendicular to the parting, having apparently grown directly 



Fig. 1. 



Fig. 1. — Photomicrograph of parting (magnification 48 diameters). The 

 hlack grains are coal ; the white are quartz ; the remainder are variously 

 oriented crystals of the mineral in question. 



through it. When fresh and unweathered the material is 

 coherent and fairly tough, but on the weathered outcrop it is 

 very friable. 



The resemblance of this material to sandstone, however, is 

 only superficial. The hand lens reveals numerous pearly 

 cleavage faces, and an almost complete absence of grit is 

 indicated when the material is ground between the teeth. 

 The grains are soft and may be scratched with the finger nail, 

 the hardness being 1*5. 



Several thin sections of this material, collected from widely 

 separated points, were prepared and examined with the micro- 



