THE CARBONIFEROUS AGE. 159 



suitable to fishes which search for food only at the 

 bottom, or only above the surface of the waters. 



Most reluctantly I must here leave one of the most 

 remarkable periods of the world's history, and reserve 

 to our next chapter the summation of the history of 

 the older world of life in its concluding stage, the 

 Permian. 



