416 M. JEFFERSON GLACIAL EROSION IN THE NORTHFIORD 



feet high, rests on the boulders of the valley floor, unencumbered. Of 

 late years the ice has been retreating. About a mile from the ice is a 

 line of moraine, shown in figure 1, plate 40. It contains no fine ma- 

 terial; only boulders like a large but discontinuous stone wall. The dif- 

 ference of vegetation on the up and down-stream sides is more striking 

 than the wall itself. Plainly the glacier stood here not many years ago. 

 The lower ledges for 500 yards along the valley are somewhat smoothed, 

 yet have not that degree of smoothing that we are accustomed to associate 

 with glaciers and which we see on the weather-stained ledges of this same 

 valley farther down or at this same point, about 1,000 feet above the valley 

 floor. One ledge that was only 100 feet in front of the ice and very prob- 

 ably covered by it last year or the year before was very much shattered 

 and its points rather bruised than rounded. Glaciated pebbles such as 

 abound in our tills were not found. The best had only the rudest sort of 

 rounding. Pebbles there were innumerable, but mostly as sharp and 

 angular as if they came from a stone quarry. The freshness of all rock 

 surfaces and the abundance of fragments, large and small, showed that 

 erosion is going on; the sharj)ness of all fragments and the shattering of 

 the ledges suggested plucking rather than grinding. The rock is a hard 

 gneiss. This ice tongue makes its mile of descent in about three miles, 

 and faces north. The water that flows from the ice is of a greenish 

 milkiness, like that of the Loen lake and the head of the fiord itself. 



BRIXDALS GLACIER 



About 10 miles from Kjendals over the ice sheet, Brixdalsbrae (plate 

 41) descends toward the west into the head of the Olden valley in 

 a continuous slope from the towering Jostedalsbrae above to a level 

 960 feet above the sea, unbroken by any cliff. It is therefore much 

 cleaner in its lower part than the Kjendalsbrae, which contained many 

 blocks of stone. At Brixdals there were none. This glacier is actively 

 grinding and polishing its bed and shaping its boulders and pebbles. 

 Along the whole 2% miles that its valley reaches back from the main 

 Olden valley, the abundant boulders are rounded and glacially planed. 

 At the head of the main valley, too, lies an ice tongue, the Maelkevolds- 

 brae. A little below the junction of the two valleys is an old moraine 

 of enormous angular blocks, black with weather. I estimate some of 

 them at 40 feet on an edge. All the detritus is black and weathered to 

 within 2 miles of the ice; thence fresh, gray, and unweathered as at 

 Kjendals. Glaciated boulders a foot or more in diameter are easily 

 found ; smaller ones are not so abundant and show no strige, owing prob- 

 ably to the granular character of the I'ock. 



