THE I[RON-FORMATION ON BELCHER ISLANDS 415 
origin—some sort of mound constructed by natives. However, the 
finding of the fragments of a quartz vein, which had cut the basalt 
strewn across the pile in a straight line, showed that without doubt 
the blocks had been heaved up by the frost. The hollow in the 
top is due to the expansion of the ice forming in the depression, 
thus crowding the rock outward and upward. 
GEOLOGICAL FORMATIONS 
The islands are made up of a thick series of interbedded igneous 
rocks and sediments. ‘To the group of sediments the name Belcher 
series has been applied, and the igneous rocks have been designated 
the Tookcarak diabase and basalt because of the fine exposures of 
these rocks on the island of that name. 
There is a close relationship between these formations and 
those on the Nastapoka Islands and in Richmond Gulf, already 
described by Low* and Leith,? and they represent deposits of the 
same system made farther offshore. ‘There is also a very marked 
resemblance between them and the Animikie and Keweenawan 
formations of the Lake Superior region. The following strati- 
graphic section may be taken as typical of the thickness and char- 
acter of the Belcher series and thé associated igneous rocks in the 
eastern part of the islands: 
FEET 
1. Flow of basalt, ellipsoidal and amygdaloidal.................. 230-++ 
2. Iron-formation consisting of jaspilite, chert, cherty-iron-carbonate, 
greendliteshematites magnetite and shales. ...0 ice. 6 4. ce 450 
3. Pink, white, and gray coarse-grained quartzite with bands of 
coarse brown sandstone and arenaceous limestone............ 512 
4. Coarse brown sandstone and arenaceous limestone interbedded 
with pink and white quartzite grading into bands of gray schist 
GIGS LST RY I IT ear Ct UL Ase Dont Ge a A Se 2,304 
Cee DTA ASC y SUE eel fa tl bie emma cae RNUE, io pio pvc LAI Wiis tue nh ky 8 
6. Gray, green, red, and white very distinctly banded slate and 
shale varying from calcareous to siliceous and locally containing 
Penhapsi2s5) pel Centyonirommet ye. epee me ee i wa gio 
* A. P. Low, “‘Geology and Physical Character of the Nastapoka Islands, Hudson 
Bay,” Ann. Rept. Geol. Surv. of Canada, XIII (1903), Part DD. 
2 C. K. Leith, ‘“‘An Algonkian Basin in Hudson Bay,” Economic Geology, V (1910), 
227-46. 
