218 A - S - PACKARD, Jr., ON THE GLACIAL PHENOMENA 



irregularly alternating bands of syenitic gneiss appeared to be an altered quartzite, as it 

 was found under a glass to be largely composed of a fine granular quartz rock, with a little 

 flesh colored and white feldspar, and minute particles of hypersthene 



Several boulders of chert occurred at Tub Island. This was a very tough compact 

 silicious rock, lmeated by fine veins of quartz. It weathers to a dull chalky white 



It is most probable that these rolled stones were borne down from the interior by glaciers 

 but the chert pebbles may have been borne on floating ice from Frobisher's Bay as Mr' 

 Hall notices such rocks as being abundant there. At Tub Island I was shown specimens 

 of magnetic iron ore, which were brought from « Cartwright's Tickle," a few miles toward 

 the main land. It occurred in veins half an inch wide. 



Should further search prove the existence, in connection with this quartzite of beds of 

 a true conglomerate, which we should look for in the interior, and of the presence of copper 

 ore in connection with the quartz veins near the trap rock, the identity of this formation 

 with the Huroman rocks of Canada and similar rocks in Sweden would seem satisfactory ■ 

 and if proven, will be interesting not only to the geologist, but be of practical value in' 

 the search for ores on this coast. 



Quaternary Formation. 

 In studying the drift phenomena of Labrador as compared with those of the temperate 

 zone we sha 1 at the outset find ourselves disappointed in our anticipations as to their 

 relative development In a region which has evidently been exposed to the most intense 

 action of glaciers, prolonged over a period vastly longer than in Canada or New England 

 we have survivmg this period of denudation and wasting away of the surface, but few° drift' 

 scratches remaining on any exposed surfaces below a height of 500 feet above the sea- 

 and superficial deposits which are reduced almost to a minimum as compared with those' 

 of the temperate zone. L 



In this absence of drift and more recent deposits, the Labrador plateau agrees exactly 

 to the 7T a 7 ll f \f S . tr f S > * bove *» level of most deciduous trees. We are to look 

 to the lowlands about their base for the debris and drift borne down by streams or glaciers 

 from the mountain centres. The Labrador plateau has been greatly denuded. Its highe 

 mountains have been truncated, and their peaks sliced off by°the denuding agent as if by 

 a knife. The quartzites of Domino have lost at least 300 to 400 feet of thefr comparatively 

 soft s rata, as evidenced by the lofty trap hills which now rise above the strata of alter d 

 andstone. The trap is as firm and hard at the top of the overflows as at the base. The 

 loose matenal resulting from this long continued denudation is not now found in the 

 intenor or on the coast of Labrador, except in very small quantities. It was evident 

 conveyed sou hwards by icebergs and floe or shore-ice, and forms the bottom of the S f 



i^:rsSn^atSs^; hoals so " in ^ " «* * «* 



In all temperate regions the superficial deposits have been characterized by Prof Desor> 

 to be a succession of rocky hills and drift plateaus or valleys, which can be 7 traced to the 

 highest elevation of the country, near the dividing ridge, each following plateau or valley 

 being commonly at a higher level than the preceding." This state of things obtains in 

 Labrador, but there is an immense disproportion between the rocky hills and the IS 

 deposits. We find no sandy plains or level tracts of glacial drift, or marine clays, distributed 



' Foster and Whitney's Report on the Geology of Lake Superior. 



