NATURAL AREAS AND REGIONS 



103 



GEOLOGY 



Over the greater part of the Labrador 

 Peninsula, probably nine-tenths the 

 area, the Laurentian gneisses and 

 schists form the country rock. These 

 consist of highly metamorphosed and 

 foliated clastic and igneous rocks of 

 great geologic age, all, with a few ex- 

 ceptions, Pre-Cambrian. More or less 

 interfolded with these aged Laurentian 

 rocks are several widely separated areas 

 of Huronian clastic and volcanic rocks, 

 and many basic eruptives schists, con- 

 glomerates, breccias, and others. Rest- 

 ing unconformably upon these aged 

 Laurentian and Huronian rocks, sand- 

 stones, argillites, shales, and lime- 

 stones, of doubtful age, with bedded 

 traps and other basic or volcanic rocks, 

 may constitute an early Cambrian 

 deposition. 



In the long period between the folding 

 of the Laurentian and Huronian rocks 

 and the submergence when these sedi- 

 ments were laid down, the peninsula was 

 profoundly sculptured and denuded to 

 the fundamental basic form and physi- 

 ography it has today the great central 

 plateau, the lake and valley basins, 

 and the fjords and inlets. 



In relatively recent geologic times this 

 old original land surface has been con- 

 siderably modified by glaciation through- 

 out its entire extent except the highest 

 mountain areas along the northeastern 

 coast of the peninsula. The central 

 neve" from which this glaciation pro- 

 ceeded, moved progressively northward 

 in three distinct successive periods of 

 ice accumulation, with intervening pe- 

 riods of diminished glaciation. The 

 earliest ice-flow radiated from a central 

 gathering-ground between the 50th and 

 51st parallels near the center of the 

 peninsula; the second from a point to 

 the northwest beyond the 54th parallel; 

 and the latest from a center about a 

 hundred miles inland from the east coast 

 of Hudson Bay, between the 55th and 

 56th parallels. 



In the areas of these central neve 

 the rocks and boulders rest upon rocks 



of the same kind and evidently have not 

 been transported far. As the distance 

 from these central areas of neve in- 

 creases, the sculpturing by the ice 

 becomes more distinct; but in general 

 the amounts of erosion and change 

 wrought upon the general surfaces have 

 not been so great as is generally thought. 

 Though the ice certainly did erode in 

 one place and deposit in another to 

 reduce the surface to a general uniform 

 level over the most of the plateau, the 

 evidence does not show that it ever 

 trenched or plucked out such deep 

 depressions as it apparently did farther 

 south along the peripheral edges and 

 lobes of the ice-sheet. 



PHYSIOGRAPHY 



Outline 



The west coast of the peninsula, 

 running nearly due north and south for 

 800 mi. is remarkably straight and un- 

 broken by any deep indentations,though 

 bordered by numbers of long groups of 

 low narrow islands paralleling the shore- 

 line; the south side of the area covered 

 in this report corresponds roughly to the 

 divide between the rivers flowing into 

 the St. Lawrence and those emptying 

 westward, eastward, and northward to 

 Hudson Bay, Ungava Bay, and the 

 Atlantic. The Atlantic coast is ex- 

 ceedingly irregular, cut by many deep, 

 narrow fjords and bays, of which Hamil- 

 ton Inlet, the southernmost, is the 

 largest and deepest; and bordered by 

 islets and skerries innumerable. The 

 coast of Hudson Strait and Ungava 

 Bay are relatively regular, bordered by 

 many islets. The passages between the 

 islets and the mainland, and between 

 the islets themselves are locally des- 

 ignated as "tickles." 



Relief 



The Labrador peninsula is a gently 

 undulating plateau which rises abruptly 

 within a short distance from the coast 

 line to a general elevation of about 

 2000 ft., and which slopes rather gently 

 westward, northward, and eastward to 



