THE LERON-FORMATION ON BELCHER ISLANDS, 
HUDSON BAY, WITH SPECIAL REFERENCE TO ITS 
ORIGIN AND ITS ASSOCIATED ALGAL LIMESTONES 
E. S. MOORE 
Pennsylvania State College 
CONTENTS 
LOCATION AND AREA OF THE ISLANDS 
TOPOGRAPHY 
GEOLOGICAL FORMATIONS 
GEOLOGICAL STRUCTURE 
THE IGNEOUS ROCKS 
THE ALGAL CONCRETIONARY LIMESTONES 
THE KEEPALLOO [RON-FORMATION 
ORIGIN OF THE [RON-FORMATION 
SUMMARY 
LOCATION AND AREA OF THE ISLANDS 
The Belcher Islands have been until recently but little known 
outside of Hudson Bay, although for decades considerable trade 
has been carried on between the trading-posts on the bay and the 
Eskimos living on these islands. On most modern maps the 
“North Belchers”’ and ‘‘South Belchers”’ are indicated by small 
dots, while one chart shows a sounding of several fathoms which 
would probably fall on the main island. The old map prepared 
from Sir Henry Hudson’s notes is more nearly correct in indicating 
the size of this land mass than any which has since been published. 
These islands recently have been brought to the attention of the 
public through the work of the Sir William Mackenzie Expedition 
to Hudson Bay and Straits. This expedition was in charge of 
Mr. R. J. Flaherty, and to him credit is due for the accompanying 
outline map (Fig. 1), as minor changes only have been made in his 
original copy. Although this map is the result of a reconnaissance 
survey, it serves as a basis for travel and outlines the larger features 
of the land masses. 
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