98 



PLANTS 



the many deposits of coal, covering in the aggregate thousands 

 of square miles of the earth's surface and varying in thickness 

 from a few inches to hundreds of feet. 



Fig. 54. — Sarracenia minor. X1/2. 



220. Practically all the coal-forming plants have long since 

 become extinct. They belonged chiefly to the Cryptogams, 

 and very few of the higher plants existed at the time. The 



