310 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



• _» W 



Figure 2. — Brown thermograph and log raft as they appeared in Grebe Lake, July 1954. 



Temperature 

 (degrees F.) 



65 

 60 

 55 



50 h 

 45 



40 



£1 l 



Surface 1953 • • 

 1954 •— ■• 



Bottom 1953 °— ° 

 1954 o— «o 



6/4 6/11 6/18 6/25 7/2 7/9 7/16 7/23 7/30 8/6 8/13 8/20 8/27 



Figure 3. — Average weekly water temperatures (hourly observations from thermograph records) for Grebe Lake, 



Yellowstone National Park, Wyo., during 1953 and 1954. 



