STEVENSON— INTERRELATIONS OF THE FOSSIL FUELS. 81 



bed, which is filled with many large and small remains of firs, yews, 

 oaks, birches and alders. The stems are mostly prostrate but with 

 them are many stumps of fir and oak rooted in the bed. The same 

 author, in a later publication, asserts that a Hochmoor may originate 

 on a bed of sand if only there be sufficient moisture. To prove his 

 position, he gives a reproduction of a photograph showing the floor 

 of an extensive Hochmoor, which expanded by encroachment upon a 

 forest growing on sand. The vertical stumps are exposed where the 

 peat was removed. 



The condition is familiar in the United States; G. H. Cook, N. S. 

 Shaler, C. A. Davis, D. W. Johnson and others have considered the 

 subject in detail. Davis has described conditions in the Pocosons 

 or swamps on the coastal plain in North Carolina. But there are 

 many peat deposits which did not originate on forested areas ; those 

 have no trees rooted in the soil below. There are others beginning 

 in open area but expanding by transgression into a forested area ; 

 these have the rooted trees in one portion but not in the other. 



It is unnecessary to cite evidence that the peat itself may be a soil 

 for growth of non-water-loving trees. In every land, the peat de- 

 posits show successive forest beds, the trees being rooted in the 

 peat and not penetrating to the underclay or subsoil. Numerous 

 instances have been noted in preceding pages. But it is well to 

 emphasize the fact that the opinion that plants have repugnance to 

 thrusting their roots down into peat and that trees do not grow on 

 peat, living or dead, is wholly erroneous. Plants disliking an acid 

 soil certainly do not thrive on peat; but there are plants for which 

 an acid soil is essential. Among these are some of the largest trees 

 of America. That they have grown luxuriantly is certain, for in 

 many of the extensive peat deposits in this country, the peat is com- 

 mercially worthless because it is so crowded with stumps and stems. 

 In many vast swamps of the coastal plain, a sounding rod cannot be 

 thrust to the bottom and a similar condition has been reported from 

 many places in the interior. 



The Roof or Toit. — The roof of a buried peat bog may be as 

 variable as the floor. It may be sand, clay or marl, freshwater or 

 marine; the transition may be gradual, a faux-toit consisting of 



