Micliigiiii CieoloKiciil ami 

 Biological Survey. 



l^iililiialiuii 20: Hioloiry I. 

 I'luli- II 



SOUTH TWIN LAKE. LOOKING NORTHWEST, SHOWING BROAD SHOAL WITH 

 A SCANT lU'SlI f;i{()\\ TH AM) ITIK ZONKS OF SHoin-: XKGKTATION. 



