Explanatory Note 



The series embodies results of investigations, usually of restricted 

 scope, intended to aid or direct management or utilization practices and 

 as gioides for administrative or legislative action. l'=^ is issued in 

 limited quantities for the official use of Federal, State or cooperating 

 agencies and in processed form for economy and to avoid delay in publica- 

 tion. 



Washington, D„ C. 

 February, 19^2 



