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GEOLOGY OF THE LAKE OF THE WOODS. LAURENTIAN AND a Prt 
HURONIAN. eh on 





















PosITIoN AND GEOGRAPHY OF THE LAKE—Clear-water Lake—Sand-hill Lake — 
White-fish Lake—Lac Plat—FormER GroLogicAL ExpLoRERS—LAURENTIA} 
FormMatTion— Vicinity of the North-West Angle—Flag Island to Rainy - Rae 
. — Bigsby Island-—Middle Island—North Island—Shebashea—AREA o¥ ei 
Ne ALTERED HURONIAN.—INTRUSIVE GRANI?TIC Mass or NgrrH-Wxst ANGLE 
—Its form—Northern branch—Southern branch—Included area of altered 
rocks—Hvurontan Rocks—ANG@LE InteT To Ka-KA-KE-wABEC—Quartzite— 
Conglomerate belt—Schistose rocks— Second Conglomerate belt— Second ee 
Schistose belt—Ka-KA-KE-WABEC GRANITE—Hvurontan Rocks KA-KA-KE 
WABEC TO Rat PortracE—Schistose belt—Conglomerate of Lacrosse Island— = 
Extensive Schistose belt with some conglomerates—JUNCTION OF THE LAU- a 
RENTIAN AND HvuRoNIAN AT RAT PorTAGE—GENERAL DISTRIBUTION AND 
ATTITUDES OF THE Rocxs—Main directions of flexure—Comparison with 
=% ; other localities—CHARACTER AND AGE OF THE SO-CALLED HuroniaN Rocks 
ay Nature of the conglomerates—Metamorphism—Dykes and veins MINERALS ey: 
A OF ECONOMIC VALUE, 

Position and Geography the Lake of the Woods. 
ee: 37. The Lake of the Woods is over seventy miles in extreme length, 
and from its exceedingly irregular form has a very extended coastline. It = 
belongs to that system of inland waters which includes the Great Lakes to ; 
the east, and is continued in the north and west by Lakes Winnipeg, Atha- 
basca, Great Slave and Great Bear Lakes; all of which lie along the 
southern and western margin of the great metamorphic nucleus of the = 
continent, where its crystalline rocks sink below those of Silurian and 
Devonian age. his lake, in its geographical and geological relations, | | 
thus differs from those which cover so great a part of the surface of the : 
crystalline metamorphic series itself, and which appear to occupy shallow 
rock basins in it. 
38. The water supply of the “lake's is derived chiefly from the north- 
ward and eastward by the Rainy River, a magnificent stream, draining the — By 4 
western slope of the watershed which divides the waters flowing to © 
the Lake of the Woods, from those falling eastward into Lake Superior. 
The tributary streams from the country lying west of the lake, though 
comparatively numerous, are unimportant; as the low ridge which separates 
these from those passing westward into the Red River, lies very near 


