FERNS, FERN ALLIES, AND FOSSILS. 



281 



interrupted by stretches of water full of the creeping 

 rhizomes of living plants, and of decaying vegetation. 

 The temperature was higher than it is in the tropical 

 forests of to-day ; and the continual mists produced a 

 dim, shady light, such as that found nowadays in the 



Fig. 35. — A Clubmoss (Lycopodium clavatum). To show the root-bearing 

 projections or branches below and the flowerlike clusters of spore leaves at the 

 ends of the upper branches. Photograph from a herbarium specimen (collected, 

 R. Kennedy, 1850). 



places most frequented by ferns. In such a warm, 

 steamy atmosphere, both growth and decay were 

 exceiedingly rapid. The spores, protected by the 

 resin which they contained, did not decay so fast as 

 the other parts. Our coal is, in fact, largely made 

 up of spores of Fernlike and Lycopodiaceous plants, 

 whilst the mineral, or mother of coal, represents 

 decay-products and the shreds of bark and leaves. 

 Through forest swamps of this kind there meandered 

 rivers, which deposited in their basins masses of 

 vegetable pulp mixed with silt. These beds have 



