130 The American Geologist. June, 1894 
the surface unequaled elsewhere in the world,.but the more volatile and 
valuable constituents of the oil have long since disappeared, and the 
rocks from which ii issued arc probably exhausted as the How has 
ceased." 
Mr. J. B. Tybbell contributes a memoir of 235 pages, on nor! hwestern 
Manitoba and portions of the adjacent Districts of Assiniboia and Sas- 
katchewan: During the Tertiary era great denudation of the Creta- 
ceous strata <>l' thai region was forming the present valleys of the 
Saskatchewan. Red Deer, Swan. Valley, and Assiniboine rivers, and the 
broad lowland plain which holds in its extensive but shallow depressions 
lakes Winnipeg, Manitoba, and VTinnepegosis. From this plain of the 
ureal Manitoba lakes the Cretaceous rocks were almost entirely denuded 
down to the underlying Moor of Paleozoic limestones. The main stream 
of the river system effecting this erosion appears to have flowed north- 
westerly through Manitoba. Farther north it probably traversed the 
present areas of Hudson bay and strait, having belonged to a time of 
gradual uplift of the continent much above its present hight, preced- 
ing-and finally producing the [ce age. The observations of glacial striae 
show that the ice-sheet flowed southward across the high Assiniboia 
plains, and southeastward over the Manitoba lake district. Till thinly 
covers the Paleozoic rocksof thai district: hut it is thicker, and is fre- 
quently accompanied by overlying beds of modified drift upon the vast 
plateau of < Iretaceous shales on i he west . 
The report of Dr. Robert Bell, on the Sudbury mining district, oc- 
cupies 95 pages, including four appendixes. The accompanying map is 
sheet 130 of tin; ( Jiita rio series of the Survey, covering 72 miles from 
east to west by 48 miles from north to south, and comprising the nickel 
deposits which have become so celebrated during the last few years. 
The rocks are successively of Laurentian, Huronian, and probably 
Lower Cambrian age, with large areas of pyritiferous greenstones in the 
Huronian series. The ores of nickel are always found in association 
with pyrrhotite. which forms brecciated masses in the greenstones or at 
their contact with other rocks. The average amount of nickel in this 
iron sulphide is only two to three per cent., but richer ores are found in 
small quantities. Dr. Bell considers that the nickeliferous pyrrhotite 
has resulted from a state of fusion. Among other economic minerals 
of the district, ores of copper, lead. zinc, and gold are enumerated. 
Hunters" Island, a large Archean tract, almost completely surrounded 
h\ canoeable streams and lakes, adjoining the northern boundary of 
Minnesota, is described by the late Mr. \Y. H. ('. Smith. The gneisses 
and schists commonly present the topographic features of rounded 
hills and roches moutonnies, with plentiful drift. Courses of glacial stri- 
atum range from s. -2° W. to s. 4:: \Y. 
Describing the southern portions of Portneuf, Quebec, and Montmor- 
ency counties, which reach from the watershed south of lake St. John 
to the St. Lawrence, Mr. A. P. Low remarks the nearly due south 
course of all the glacial strire on the comparatively low country north 
of that lake, which is 350 feet above the sea. Thence t hi' ice-sheet car- 
