Page:Quarterly Journal of the Geological Society of London, vol. 33.djvu/195

Rh AND CIRQUES IN NORWAY AND GREENLAND.

157

charged by a great fjord as " one or several thousand million cubic ells," states that this amount is many times smaller than that of the rain and snow which falls upon the interior of Greenland. Even if, as I am inclined to do, we read cubic metres for cubic ells in the above, still the proportion discharged as ice will be much smaller than that which passes out as water beneath the glaciers.

On the amount of mud in Rivers issuing from. Glaciers in Greenland and Norway. — The sea-water of the fjords into which glaciers de- scend is not muddy ; but where a strip of shore intervenes between the water and the ice a muddy river is seen to issue from the glacier ; also along the sides of the glaciers in the fjords and along the In- land Ice, streams thick with pulverized rock are often to be seen. The rivers which discharge themselves into the fjords under the great glaciers, often far from the end of the latter, probably deposit their mud at the bottom of the sea beneath the ice.

The quantity of mud in the rivers which issue from the glaciers in Greenland is very variable, as will be seen from the following numbers (these indicate the weight of mud in grams in 1,000,000 grams of water, which is nearly the same as the quantity of mud in grams contained in 1 cubic metre of water) : —

River at the glacier of Jakobshavn 9th of July, 1875

„ „ Alangordlek 10th of July, „

,, „ Ilartdlek 17th of July, „

„ ,, Tuaparsuit 6th of Aug. „

„ ,, Umiatorfik 20th of Aug. ,,

„ ,, Assakak 21st of Aug. „

„ „ Kangerdlugssuak 1 lth of Aug. ,,

Grams of mud

in 1 cubic metre

of water.

104

2374

723

678

75 208 278

The last four glaciers are situated in the district of Umanak.

In Norway the quantity of mud in the rivers issuing from under the glaciers descending from the large snow-and-ice field of Juste- dalsbraeen was calculated in the year 1874. The numbers were as follows : —

The western river of the glacier of Boium 23rd of June

The same river 30th of July

The eastern river of the glacier of Boiurn 23rd of June

The same river 30th of July

The large river of the glacier of Suphelle 24th of June

The same river 30th of July

The small river of the glacier of Suphelle 24th of June

The small river of the glacier of Langedal 6th of July

The river of the glacier of Austerdal 6th of July

The ri ver of the glacier of Brixdal 1 6th of July

Grams of mud iu 1 cubic metre of water.

309 59

159 33

113 72

513 56 77

Mean number 1479

It is obvious that even the quantity of mud in the same river is very variable.

By measuring the quantity of water in the rivers, I calculated the quantity of mud carried away from all the glaciers descending from