Explanatory Note 



The series embodies results of investigations, usually of 

 restricted scope, intended to aid or direct management or utilisation 

 praotioes and as guides for administrative or legislative action. It 

 is issued in limited quantities for the offioial use of Federal, State 

 or cooperating Agenoies and in processed form for eoonomy and to avoid 

 delay in publication. 



sreoi 



