BITUMINOUS COALS 209 



Fig. 40. — Spore-exine very common in the coal from Sessor, Illinois, but 

 found in other coals from bed No. 6. X i ,000. 

 Fig. 41. — A spore-exine common in all coals. 



PLATE XI 



Fig. 42. — Cross-section of a pyritized fossil stem of Medullosa Anglica, 

 showing three steles, surrounded by a common periderm; next to this is the 

 inner cortex forming the outermost zone of tissues. The inner and outer cor- 

 texes are pervaded by leaf traces and gum ducts, both recognizable, though not 

 distinctly in the photograph. 



Fig. 43. — Fart of a cleavage surface of coal, showing a large number of 

 "rodlets" or "needles" imbedded helter-skelter in the attritus. X 10. 



Fig. 44. — Part of a horizontal cleavage plane of coal showing a Medullosa 

 type of woody structure, in which "needles" or "rodlets" form part of the 

 tissue. X 3. 



