13 
currents which sweep anti-clockwise around Hudson Bay, and 
its frozen condition for seven months of the year, explain the 
southerly dip of the tree line and the summer isotherms. ” 
According to Ritchie (1956), most of the Churchill area 
“is covered by till of Pleistocene age, consisting of silt, calcar- 
eous clay and pebbles, boulders, and rock flour. The land which 
is covered by this till is flat or gently sloping, forming the vast 
plains of much of Northern Manitoba and Keewatin, broken only 
by outcrop ridges, eskers, moraines, raised beaches, and shore 
lines.” 
Climate of Churchill 
Tables I and II have been compiled from Volume 1 of * ‘Cli- 
matic Summaries for Selected Meteorological Stations in the 
Dominion of Canada,” issued by the Meteorological Division of 
the Department of Transport, Canada. The localities chosen are 
indicated by the following numbers: (1) Winnipeg; (2) Brandon; 
(3) Swan River, north of Duck Mountain; (4) Berens River, about 
the middle of the east coast of Lake Winnipeg; (5) The Pas; (6) 
Norway House; (7) Port Nelson, and (8) Churchill. 
Table I 
Monthly and Annual Averages of Daily Mean Temperature 
(degrees Fahrenheit) 
1 
2 
3 
4 
5 
6 
7 
8 
Years obs 
66 
29 
11 
19 
27 
40 
11 
30 
J an u ary 
-3 
-3 
-6 
-8 
-9 
-11 
-17 
-19 
F ebruary 
2 
1 
-6 
-3 
-2 
-4 
-14 
-17 
March 
16 
16 
9 
10 
11 
9 
2 
-6 
April 
38 
38 
39 
31 
33 
29 
17 
14 
May 
52 
51 
49 
56 
48 
45 
33 
30 
June 
62 
60 
59 
58 
59 
57 
45 
43 
July 
67 
65 
64 
63 
65 
63 
55 
54 
August 
64 
62 
61 
60 
61 
60 
53 
52 
September 
54 
53 
51 
50 
49 
48 
44 
42 
October 
41 
40 
38 
36 
35 
36 
30 
27 
November 
22 
21 
18 
19 
17 
16 
10 
6 
December 
6 
6 
2 
0 
1 
-2 
-9 
-11 
Annual Average 
35 
34 
31 
30 
31 
1 
29 
i 
21 
18 
