BITUMINOUS COALS 207 



Fig. II. — Part of the thin cross-section shown in Figure 5, at a higher 

 magnification, a-i is a thin anthraxylon chip, showing some plant structure; 

 d-2, a thin sheet of attritus, containing a large amount of spore matter, some 

 humic matter, and some earthy matter; a-2,, anthraxylon chips; d-/^, attri- 

 tus. X 200. 



Fig. 12. — Part of a thin horizontal section of coal from Terre Haute, 

 Indiana. While the cross-sections reveal but very little plant or woody 

 structure, every horizontal section shows a large amount of it, as in this section. 

 X 150. 



PLATE Vn 



Fig. 13. — A close-up view in a typical Wisconsin peat bog. 



Fig. 14. — A lump of dried peat from the bog shown in Figure 13, showing 

 thin chips of woody peat or anthraxylon, imbedded in the attritus. Compare 

 this wdth Figure 4. Natural size. 



Fig. 15. — The thin flat pieces of woody peat, picked out of the lump shown 

 in Figure 14. Natural size. 



PLATE vm 



Fig. 16. — Part of a thin cross-section of the coal from Ziegler, IlHnois, con- 

 taining a large proportion of cuticular matter. X 10. 



Fig. 17. — Part of a thin cross-section of coal similar in appearance and 

 composition as that shown in Figure 16. The heavy white lines running across 

 the photograph represent leaf cuticles imbedded in matter largely derived from 

 leaves. X 200. 



Fig. 18. — One of the cuticles separated from the coal and seen flat-wise. 

 X 200. 



Fig. 19. — Part of a thin cross-section of a Pittsburgh coal with a number 

 of thin anthraxylon strips, d-i, attritus rich in humic matter; a-2, thin 

 anthraxylon strips rich in resinous matter; J-3, attritus; c-4, anthraxylon 

 strips; J-s, thin layer of attritus; a-6, anthraxylon strip; J-y, attritus. 

 Cell structures have been retained in a-4 and a-6. X 200. 



Fig. 20. — Part of a thin cross-section of Pittsburgh coal rich in attritus. 

 d-i, attritus composed of humic matter, spore-exines and carbonaceous 

 matter, a-2, a thin anthraxylon layer; J-3 attritus composed of humic 

 matter, spore-exines, and carbonaceous matter; a-4, a very thin strip of 

 anthraxylon; J-5 and d--], attritus, composed chiefly of spore-exines, some 

 humic and carbonaceous matters, including thin strips of anthraxylon. 



PLATE IX 



Fig. 21. — Part of a thin cross-section of the coal from the Pittsburgh seam, 

 at a very high magnification, showing the constituents in detail: spore-exines, 

 in white; humic matter in gray; resinous particles, homogeneous gray, and 

 carbonaceous matter in black. X i ,000. 



