Correspondence. 383 
CORRESPONDENCE. 
Lake Superior Stratigraphy. In your May number Dr. Lawson 
has a criticism* of a recent paper of minef in the American Journal of 
Science upon Lake Superor Stratigraphy, in reference to which I ask 
space for a few remarks. 
In the first place, while Lawson mentions our past and present general 
agreement, he so emphasizes the points of difference that one would not 
become aware from the review how close this agreement really is. The 
district considered by Lawson is only one of several in the Lake Superior 
region which were discussed by me. If the criticisms were wholly true 
of that one district they would not disprove the correlations for the 
others. I am in harmony with, and understood before the appearance 
of the criticism, the four propositions^: made as to the relations of the 
Animikie, Keewatin, Coutchiching, and the gneiss and granite which 
Lawson recognizes as Laurentian, except that I have no knowledge 
whether or not the pre-Animikie erosion is "the greatest in American 
Geology." From the criticism, although I do not suppose this was in- 
tended, one would certainly infer that there is a fundamental difference 
in the successions proposed by Lawson and myself. I submit a parallel 
arrangement of our stratigraphical columns for western Ontario, omit- 
ting major taxonomy. 
Succession in western Ontario Succession in ivestem Ontario 
according to Van Hise. 1 according to Lawson. 2 
Nipigon. Keweenawan or Nipigon group. 
Unconformity. Unconformity. 
Animikie and Upper Animikie Group. 
Kaministiquia. (Possibly Huronian). 
Unconformity. Unconformity— Greatest erosion inter- 
val in American Geology. 
Keewatin in part at least, Keewatin Group. 
and Lower Kaministiquia. (Possibly Huronian.) 
Unconformity? Unconformity? 
Coutchiching. Coutchiching Group. 
Eruptive Unconformity. Irruptive Unconformity. 
Laurentian. Laurentian System. 
The rock succession is seen to be nearly identical, with identical 
relations. Lawson says that my table presents an "undesirable incon- 
gruity " in that the Laurentian rocks are made more ancient than the 
Keewatin, when they cut them. That I recognized that the granite- 
gneiss of Rainy lake and the Lake of the Woods cuts the Keewatin is 
*Lake Superior Stratigraphy, Andrew C. Lawson: Am. Geol., vol. 7, pp. 320-327. 
tAn Attempt to Harmonize some apparently conflicting views of Lake Superior 
Stratigraphy, C. R. Van Hise: Am. Jour. Sci., vol. 41, pp. 117-137. 
+Ibid, p. 322. 
^Ibid, p. 137. 
a Ibid pp. 326-327. In this succession in the original table Irruptive Unconformity 
and Laurentian system are transferred under Coutchiching in order to give a 
columnar arrangement. The Irruptive Unconformity and Laurentian Systemill 
the table are so arranged as to apply both to the Coutchiching and Keewatin 
