PUBLICATIONS. 351 
According to Lawson a very evident relationship exists between the 
topography of the north side of Lake Superior and the geological struc- 
ture ofthe region. From Duluth eastward the Keweenian, Animikie and 
Archean constitute successive geological provinces marked by character- 
istic topography. The Potsdam is represented to a limited extent in the 
vicinity of Sault Ste. Marie, and is of especial interest as forming the 
dam in St. Mary’s River which holds the waters of the lake at their 
present level. The beaches, bars, spits, deltas and wave-built terraces 
are described in detail. The highest mark of submergence was found 
at Mt. Josephine at a height of 607 feet above the lake (1208), while 
the number of strands recognized in at least two localities was thirty- 
one, ranging up to a height of 534 feet (1135). This was the level of 
the highest strand noted at Duluth, while at Sault Ste. Marie the 
highest was 413 feet (1014). It is evident, however, that owing to the dif- 
ficulties attending observation the record of the higher strands is very 
incomplete. On the supposition of the lowering of a lake barrier to 
the southeast it is evident that the outlet of the vast sheet of water 
represented by these strands shifted from time to time in consequence 
of continental warping. The evidence of an outlet into Hudson Bay 
referred to by Taylor is given and others noted. 
Observations at Mackinaw Island had shown the existence of a 
shore line 205 feet above the lake (786) which was correlated with the 
Algonquin beach of Spencer, and the belief was entertained that an 
old outlet of Lake Warren would be found at Nipissing. Later inves- 
tigation, the details of which are given in the fifth paper, corroborated 
this conclusion. This ancient strait, as defined by the two highest shore 
lines, was about thirty-two miles wide where observed, narrowing east- 
ward to about twenty-five miles. Its depth over the low pass between 
Lake Nipissing and Trout Lake must have been nearly 500 feet. 
The last paper by Mr. Taylor records the results of observations 
between Lakes Simcoe and Nipissing, where the altitudes of the highest 
beaches observed range from 780 feet above sea level at Barrie to 1140 
at North Bay on the east shore of the latter lake. The identity of the 
upper beach of the Nipissing region with the Iroquois or Algonquin 
beach of the Ontario basin is reaffirmed. 
The eastward rise of the Algonquin beach noted by Dr. Spencer in 
the region west of Lake Simcoe was corroborated. Great silt-beds 
were found showing singular alternations of clay and silt in lamine 
often not more than one-half inch in thickness. The evidence is con- 
