OF PRE-CAMBRIAN ROCKS 217 
Cambrian—Potsdam sandstones, etc. 
(Unconformity) 
Pre-Cambrian 
Grenville series 
(Intrusive contact) 
Laurentian 
The committee consider that it is inadvisable in the present state 
of our knowledge to attempt any correlation of the Grenville series 
with the Huronian or Keewatin, so extensively developed in the 
region of the Great Lakes. The Grenville series has not as yet 
been found in contact with either of these, and until this has been 
done and the relations of the several series have been carefully studied, 
their relative stratigraphical position must remain a mere matter of 
conjecture. 
F. D. ADAMS 
A. E. BARLOW 
A. P. COLEMAN 
H. P. CusHine 
J. F. Kemp 
C. R. Van HIsE 
