128 The American Geologist. August, i897 
and at Missanaibi. According to Lawson the altitude of the 
cols in these passes is 500 feet and 440 feet above the lake re- 
spectively. Measuring from Missanaibi station, however, the 
latter col proved, according to the Canadian Pacific railway 
profile, to be about 515 feet or 75 feet higher than the altitude 
given by Prof. Lawson. If the Algonquin plain is approxi- 
mately even from Cache lake to Sault Ste. Marie this would 
leave the col at Missanaibi about 85 or 90 feet above the beach, 
and the col near Jackfish is nearly the same distance above the 
beach at that place. So the idea of straits to Hudson bay had 
to be given up and with it also the hypothesis of marine ori- 
gin for the higher beaches. Subsequent observations in the 
Ottawa valley fully confirm the alternative hypothesis, name- 
ly, that the water which made the liigh shorelines of the 
northern lakes was held in place by a great ice-dam in the 
Ottawa valley, and that these lakes were incidental to the re- 
treat of the ice-sheet.* 
EDITORIAL COMMENT. 
Light in the East. 
The following extract is from the Fopular Science 3foiifhlii 
,)fjuly: 
Dr. Ebenczer Emmons mid the OleneUus. During the geological sur- 
vey of the state of New York which, commenced in 1836, was almost the 
first of the geologicar surveys that were entered upon and properly pros- 
ecuted in the United States, there was a marked difference of opinion 
between Prof. Ebenezer Emmons, of Williams College, who had charge 
of the portion of the survey that embraced the rocks of western Massa- 
chusetts and the upper waters of the Hudson, and his associate geolo- 
gists, which finally terminated in a bitter personal antagonism and 
almost total ostracism of Dr. Emmons. The point at issue was mainly 
the relationship in respect to position and age of the rocks in question, 
especially those typified by the strata of Greylock mountain and the 
Hoosic valley. The position taken by the majority of the associate ge- 
ologists on the survey was that the so-called Silurian system of rocks 
constituted the base of the fossil iferous rocks of New York, and infer 
entially of the whole country, and that the so-called "Potsdam sand- 
*Am. Geol., vol. Jjvii, April 1896, pp. 253-257. 
Am. Geol. vol. xviii, August 1896. pp. 108-120. 
Inland Educator, Terre Haute, Ind. April 189G, pp. 138-145. 
"Studies in Indiana Geography." Inland Publishing Co., Terre Haute. 
Ind. 1897, Chapter x, pp. 104-105. 
