156 STEVENSON— INTERRELATIONS OF THE FOSSIL FUELS. 



sists of one to 3 inches of " black jack," a stiff, black coaly material 

 with fragments of wood and stems. The coal is clean and solid 

 for 6 feet; above that it is streaked with thin washes of white sand 

 and dirt and irregular lenses of sand which seem to be in ripples. 

 Higher, the sand washes are thicker and at length predominate, 

 with intervening black muds, carrying waterworn vegetable ma- 

 terials. Above this is compact laminated clay, 3 feet thick, with 

 many stems and traces of what appear to be roots. The upper part 

 of the dirty coal, where it begins to be laminated, is rather distinctly 

 marked with roots, branching rather irregularly downward and some 

 of them appear to have extended a long distance into the coal below. 

 Many of these seem to have rotted and the cavities to have been 

 filled with white sand and clay, disfiguring the coal. Amber or 

 fossil resin is abundant in some layers and the coal has joints, 10 

 to 12 feet apart. The lower bed rests on drab clay, filled with roots 

 in place, which is covered by a thin layer of old humus, followed by 

 more than 6 feet of black, splintery coal with conchoidal fracture, 

 becoming dirty and laminated on top. On this rests light-colored 

 clay with carbonized roots, 10 to 30 inches thick, which is succeeded 

 by 6 to 18 inches of coal. Tree fragments are fairly common in 

 this lower bed. White's description shows that the faux-toit is 

 characteristic at both Hoyt and Rockdale ; and that the faux-mur is 

 present throughout at Rockdale. 



At Lester, in Ouachita county of Arkansas, the lenses of cannel- 

 oid coal are such that White regards them as presenting the lignite 

 stage of cannel. The locality is in the Camden coal field, which is a 

 small, irregular and very shallow basin with extreme dimensions of 

 7 by 15 miles. The rocks are unconsolidated sands and clays with 

 some ferruginous sandstone. There is one workable coal bed, vary- 

 ing from 2 feet 6 inches to 6 feet, owing to the uneven floor. This 

 floor is usually clay and holds no roots, except in one place, where 

 it is sand and shows many roots in place. In one portion of the 

 field, a carbonaceous mud forms the bottom of the bed and contains 

 lignitized stems and twigs with fragments of ferns and dicotyledons. 

 The roof is a light gray plastic clay. The coal or canneloid lignite 

 has the general structure and appearance of a somewhat impure 



