6 Sketch of the Geology/ of the Arctic Regions. 



bly gravel consisting of green felspar, white quartz, chert and lime- 

 stone. These hills gradually diminish in altitude, and the eastern 

 branch of the riyer runs round their northern limit in lat. 69''. White 

 spruce grows as far as 68"^ where it disappears. The country thence 

 becomes a frozen morass, onward, north of the hills, seldom thawing 

 morq than six or eight inches upon the surface. 



Alluvial Islands. 



The space occupied by the various reaches of the McKenzie be- 

 tween the Rocky Mountains and the Reindeer Hills, is ninety miles 

 in length, and from forty to fifty wide. The river forms this tract 

 into islands, by the numerous channels through which it winds its way 

 to the sea. The islands are most of them flooded in the spring, but 

 annual aeeumulations of drift wood and sand, have raised some parts 

 above the reach of the annual inundations, and as far north as 68'', 

 the highest parts are clothed in summer with dwarf willows, and white 

 spruce. Sandy shoals skirt the coast, " and the whole line from Cape 

 Bathurst, in W. long. 127' as far west as the Sacred Islands in 

 W. long. 137°, presents a striking similarity of outline and structure." 



The sea coasts east of the McKenzie for many miles, are low, 

 with occasionally, gently swelling sand hills. The beaches and capes 

 are thickly sown with fragments and pebbles of limestones, red and 

 white sandstone, and sienite. Some of tjie promontories consist of 

 bluish slaty clay, with a greasy feel, compact enough to be called 

 stone, but crumbling readily in water. The cliffs are often variega- 

 ted with beautiful colors. The shale is brown, interspersed with 

 crystals of selenite, and between the leaves is filled with powdery 

 alum mixed with sulphur. The wax colored variety of alum, called 

 Ilocfe Butter, occurs in layers, the shale is covered by " a bed of poor 

 calcareous clay ironstone, which has a straight cleavage, and is 

 coated by fibrous calc sinter, and chalcedony." The soil is clayey, 

 and almost mthout vegetation. Furtlier east in a high cliff of alum 

 shale, alternating layers of Rock Butter occur again, witli crystals of 

 selenite on the surface of the shale. " Pebbles of granite, sienite, 

 quartz, lydian stone, an,d compact limestone, all coated by white pow- 

 dery marl" rest on the surface of the cliff. 



