Bo^':-Oiii cypes i The t-otal aiiiojnts oi eacn type were arrived at by visual 

 estimates.. Soft bottom was classified as sand^ silt^ mudj and clay. The 

 prese-.ice of hardpan was also noted. Hard bottom was classified as bed- 

 rock., boulders (12 inches in diameter and up), rubble (3 inches to 12 

 inches in diameter) j, large gravel (3/U inch to 3 inches in diameter) j and 

 small gravel (l/U inch to 3/U inch in diameter) „ 



Spawning sites ; Gravel deposits were classified as follows (in order of 

 suitability) ; 



lo Concentrated 



a. Gravel bars and ridges on riffles. 



bo Continuously flat,, pavement-like formations in 

 riffle areas o 



2c Scattered 



a. Patches of large gravel. 



bo Discontinuous^ variable amounts of gravel in or 

 upon other substrata, 



Co Gravel mixed with rubble and boulders. 



Possible number of nests; A visual estimate was made of the possible 

 number of nests which could be constructed on the gravel formations 

 present. 



Barriers ? Classified as natural or man-made o Great Lakes sea lampreys 

 cannot ascent smooth perpendicular barriers which are 3 feet or more in 

 height. Their ability to ascend broken and irregular rock formations is 

 greater; they have been observed negotiating a falls 7 feet high, which 

 had a f ace of irregularly eroded limestone. 



Adult lampreys and nests s Locations and numbers of nests were recorded 

 with accompanying notes on type of spawning material, quality of gravel 

 formations, and other factors. The numbers of adult lampreys were 

 recorded in relation to activity (swimming, resting, spawning), condi- 

 tion (unspawned, oartially spawned, spent, dying, or dead), and location. 

 Samples of lampreys were collected and preserved. 



Larval lampreys; During the 19^0 survey, almost all streams were 

 examined at various distances below spawning habitat for larvae, which 

 were collected from all types of habitat by digging. All larvae were 

 preserved for identification. No attemot was made to collect larvae 

 in 1951 o 



