228 THE CANADIAN NATURALIST. [Vol. viii. 



chart published on the 10th July, 1876, from partial surveys 

 by Stan Commander Maxwell, R. N., is a great step in advance 

 in the correct delineation of the north-eastern coast of Labra- 

 dor, but merely the entrances to the most important Fiords are 

 shown, with a note indicating there supposed depth inland. 



Islands begin to be numerous a few miles to the east of Sand- 

 wich Bay. They form a belt or zone protecting the mainland 

 all the way to Cape Chudleigh, at the entrance of Hudson 

 Straits, about seven hundred nautical miles from Belle Isle. 

 By means of the constant action of " Pan Ice" hereafter de- 

 scribed, all exposed portions of these Islands have been polished 

 with such uniformity that a perfect picture of their structure is 

 exposed to view. 



The farther to the north we advance, the more remarkable 

 are the planed surfaces. The minutest detail of stratification, 

 of undulation, dislocation, fold or vein is as clearly visible over 

 many hundred acres on low islands, as if the wide expanse had 

 been laboriously and carefully polished by artificial means. 



The low lying surfaces are still annually submitted to a re- 

 newal of the polishing process by the never failing pan ice, and 

 it is thus that in some favourable localities square miles of rock 

 show the " grain" as clearly as a well kept mahogany table 

 exhibits the grain of the wood. 



Before alluding to the general structure of the area visited 

 last summer, which by the way, is characterized by extraor- 

 dinary regularity and symmetry, I shall briefly notice the 

 means by which so much of the detail and arrangement of the 

 strata is exposed to view. The abrading and polishing agent is, 

 as already stated, pan ice, but this is assisted in a very marked 

 degree by rock cleavage. 



2. — Rock Cleavage. 



The cleavage of the old Laurentian Rocks here is generally 

 at right angles to the bedding, or nearly so, and whenever the 

 strata incline towards the prevailing direction of the ice drift or 

 thrust on the exposed coast, the wearing away is rapidly accom- 

 plished by the removal every year of large blocks, the resulting 

 surface being left in a series of steps or terraces. 



Some illustrations of these steps are seen near Hopedale, and 

 especially in Tooktoosner Bay south of Hopedale. The steps 

 are now polished and the edges neatly rounded ; they may rise 



