736 



TEXTBOOK OF BOTANY 



Oaks predomioaril: oa upland, wLtK hickories D 

 and otKer deciduous trees 

 Tamarack la bo^s 



White pine predominant 

 with hemlock on upland 

 Black spnace in boi^s 



Northern oaks and pines with spruce 



X^on Upland X 

 Black spruce in bo^s 



White spruce with black spruce 

 predominant on upland 



/ \ 



White pine and Jack pine 

 on sand anddravel terraces 



'Oack pine and white spruce 

 predominant 



30th fQQi- 



foot 



20^'' foot 



15^^ foot 



foot 



foot 



Base of peat 



Fig. 368. A diagrammatic representation of the relative abundance of tree 

 pollens in successive layers of peat in a bog in central Ohio together with the 

 forest types inferred to be living near or in the bog at the time the layer of peat 

 was deposited. The diagram should be read from the bottom upward. Data from 

 L. R. Wilson and P. B. Sears. 



