PWixtocvnc l*apti'x, Ottaira 2Itctin</ of (i. S. A. 177 
arcHca, and a few of Saxicara arcfica and five or six other 
species. At the bay of Chaleurs and in other parts of New 
Brunswick fossiliferous marine beds resting on the till show that 
this region was depressed 175 to 220 feet during the Champlain 
epoch or time of departure of the ice-sheet. The St. John sec- 
tions indicate several slight oscillations of the ice-front, as if 
it repeatedly retreated to the Carleton hills and re-advanced 
from them a short distance into the sea. The deposition 
of the Ledaclay ensued immediately after the recession of the 
ice. 
Mr. Upiia.m said, in discussion of this paper, that the occurrence 
of Yoldia arrtira as the only plentiful species in the intercalated 
clay layers of the St. John sections implies that the front of the ice- 
sheet was near. This species is now found living only in the Arc- 
tic ocean and thrives most.according to the observations of Baron 
de Geer in Spitzbergen, near the mouths of streams discharged 
from glaciers and muddy with the fine silt of their erosion. 
The (ihaii<h,n(d sfnnu/s of Lake War re ii . By Andrkw C L.VW- 
so.v. As the author was not present, and had not forwarded this 
paper, it can be reported only b}' the following abstract sent by 
Dr. Lawson for the preliminary announcements of this meet- 
ing. 
The strands of lake AVarren, on the north side of lake Superior. 
up to an elevation of l,2(l(( feet above sea level, are postglacial. 
Tt was not an ice-dammed lake. There was an outlet northward 
corresponding to one of its higher stages. A postglacial depres- 
sion of central Canada whereb}' the James bay slope was covered 
with marine sediments to a present altitude of 450 feet above tide 
and only 150 miles distant from lake Superior is correlated with the 
maximum fullness of lake Warren, and the subsequent uplift is cor- 
related with its subsidence. The strand lines show no evidence of 
deformation. In the absence of ice dams and of a gorge of per- 
manent drainage, the level of lake Warren could only have been 
lowered by epeirogenic depression along its southeastern margin. 
that is, in the region south of lakes Huron and Michigan, which 
depression is thus coeval with the postglacial uplift of central 
Canada. High terraces and beaches are known to extend along the 
north side of lake Huron from Sault St. Marie eastward, and they 
are reported on the high lands of the peninsula of Ontario; so that 
lake Warren must have been the greatest of the known late (^ua- 
