Identifier: quarterlyjourna101854geol (find matches)
Title: The Quarterly journal of the Geological Society of London
Year: 1845 (1840s)
Authors: Geological Society of London
Subjects: Geology
Publisher: London (etc.)
Contributing Library: Smithsonian Libraries
Digitizing Sponsor: Biodiversity Heritage Library

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extremely irregular, being in three great troughs(with deep lateral indents), one of these running easterly, and theother two in a northerly direction. See Map, Plate X. The immediate shores are usually low, rarely cliffs or earthybanks ; but they rise in shapeless masses of rock, often naked, withbroad marshy intervals; or in ridges, which become hills 300-500feet high at distances from the lake varying from half a mile tofour miles. The low grounds are well covered with small trees, such as arecommon in these regions, and the higher abound in Vaccinece andother useful fruit-bearing bushes. Rainy Lake is 1160 feet above the level of the sea, according toCapt. Lefroy. Its water is pure and clear, but seldom deep, andthe spring-freshets rise to the height of from 3 to 5 feet. Itsmagnetic variation is 10°-12° E. We counted 516 islands; but there are more. They are mostlysmall and marshy; and never exceed four miles in length. * Quart. Journ. Geol. Soc. vol. viii. p. 400, and pi. xxii.
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216 PROCEEDINGS OF THE GEOLOGICAL SOCIETV. (Jan. 4, The map (hitherto unpublished) whieh accompanies this paper istaken from the archives of the Canadian Boundary Commission,whose surveyors I accompanied in their circumnavigation of thislake. While they were employed on its topography, I attended toits geology. Geological conditions.—The geology of Rainy Lake is wellworth a short but careful notice, because it continues north-easterly,into a country rarely visited, the investigations of Dr. Norwood, ofDr. Dale Owens party of geological surveyors, who worked to thenorth-east from the head-waters of the Mississippi. Professor Keat-ing (Longs Expedition) and Dr. Norwood passed along the southshore only of this lake, and their observations are contained in a fewlines*. The geology cf this body of water may be summed up in thefollowing words. Chloritic and greenstone slates, gneiss and mica-slate, in proportional quantities in the order here set down, seemonce to have occupied the lake-b

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