THE CARBONIFEROUS AGE. 159 



suitable to fishes whicli 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 TVorkVs history, and reserve 

 to our next chapter the summation of the history of 

 the older world of life in its concludmg stage, the 

 Pormian. 



