CHAPTER 2 



Density (C~f) 



Kilom«t*rt 



I 





 20 

 40 

 60 

 80 

 100 



86 87 88 



APRIL 



81 37 



50 



B A 



32 





 20 

 40 

 60 

 80 

 100 



— I 

 100 



86 87 88 



MAY 



81 37 



B 



32 



FIGURE 2-2.— April and May 1976 dcnsitydr,) sections. 



21 



