James Hall, State Geologist. 



Sir : — The accompanying report is made in accordance with your instruc- 

 tions to map the northern boundary between the Potsdam sandstone and the 

 Precambrian crystallines across Franklin county and as far into St. Lawrence 

 county as practicable; further, to determine what rocks younger than the 

 Potsdam come in on the north and their limits, and, in addition, to make 

 observations on the change in the character of the gneisses in going westward. 



Respectfully yours, 



H. P. CUSHING. 



March, 1897. 



