62 



HOBBS— CHARACTERISTICS OF THE 



[April 22, 



Ice-caps of Norzvay. — In contrast with all save the Piedmont 

 type of mountain glaciers, the snow fields of ice-caps are much the 

 larger. Speaking broadly, high and relatively level plateaus, light 

 winds, and low temperatures are favorable to the existence of ice- 

 caps. Today they are not to be found in latitudes lower than 60°. 

 In Norway, within the zone of heavy precipitation along the 

 western coast, and upon the remnants of the plateau separated by 

 the fjords, are still to be found a number of small ice-caps. These 

 caps consist of a central carapace of snow and ice from the borders 

 of which narrow tongues descend into the fjords. The largest of 

 these ice-caps is the Jostedalsbraen, having an area of 1,076 square 

 kilometers. Whereas with mountain glaciers the neve is con- 

 tained within a basin, the cirque, we here find the so-called 

 " f jeld " nearly level and resting upon the surface of the plateau. 

 Of this fjeld broadly lobate extensions lie upon its margin 

 separated by deep valleys or fjord heads. Much narrower exten- 

 sions of the central carapace often descend the steep slopes at the 

 upper end of these valleys and may continue down the valley floor. 

 Their narrowness is largely explained by their more rapid motion 

 upon the steeper slope and by the reflected heat from the rock walls 

 on either side. See Fisf. 2.^ 



Fig. 2. Idealized section showing the form of "fjeld" and "brae" in 

 Norwegian ice-cap. 



Icc-caps of Iceland. — In Iceland are to be seen some of the 

 finest examples of ice-caps that are known, and, fortunately, these 

 have been carefully studied by Thoroddsen.* These ice-caps form 

 gently domed crests or undulating ice fields situated upon the 



' H. Hess, " Die Gletscher," 1904, pp. 66, 99-92. 



■'Th. Thoroddsen, "Island, Grundriss der Geographic und Geologic," Pet. 

 Mitt. (Erganznngshefts 152, 153), 1906, V., "Die Gletscher Islands," pp. 

 163-208. 



