ICE ISLAND: 



(1) (I I. A. Lb.)— Island ice. 



(2) (II.A.5.a.) — Ice island iceberg. 



(3) (II.A.5.a.) — A tabular iceberg whose extent is measured in miles. 



(4) (V.C.) — A huge mass of floating ice in the Arctic Ocean. Ice 

 islands have been estimated up to a few hundred feet thick and 

 from 20 to 40 miles across. Their shape is similar to that of tabular 

 icebergs. Their upper surfaces are covered with broad, shallow 

 undulations and have individual drainage systems. The place and 

 manner of origin of ice islands have not been determined. 



ICE ISLAND ICEBERG: (II.A.5.a.)— A conical or dome-shaped ice- 

 berg. Under various lighting conditions an ice island iceberg will 

 resemble an island in color and shape. (Fig. 98.) 



ICE JAM: 



(1) (IV.) — An accumulation of broken river ice caught in a narrow 

 channel. Cf. ice gorge, debacle. 



(2) (III.) — Fields of lake ice thawed loose from the shores in early 

 spring may be blown against the shore exerting great pressures. Also, 

 masses of broken-up ice may drift with the wind and produce jams on 

 and against the shore. 



ICE LEDGE: (I.B.l.a.)— Ice foot. 



ICE LENS: (I LB.)— Fossil ice. 



ICE LIMIT: (I.A.l.f.) — The greatest extent of ice at any given time. 



Cf. Ice edge. 

 ICE NEEDLE: (V.B.) — An ice crystal in the shape of a tiny, slender 



shaft. 

 ICE PACK: 

 (1) (I.A.I.) — Any large area of floating ice driven closely together. 

 See consolidated ice. 



(2) (I.A.I.) — The entire area of ice in the polar seas and the seas 

 surrounding Antarctica (Figs. 23, 49, 50, 61) . 

 ICE PILLAR: (II.B.) — A pedestal of ice on a glacier supporting a 



broader block of stone that has protected the ice beneath it from solar 



heating (Fig. 100). 

 ICE POLE: (V.C.) — The center around which is located the more con- 

 solidated portion of the arctic ice pack. The Ice Pole, or Pole of 



Inaccessibility as it is sometimes called, lies in the vicinity of latitude 



83° to 84° N. and longitude 160° W. 

 ICE-PUSH TERRACE: (III.)— The comparatively permanent materials 



along a lake shore shoved up by successive ice ramparts. 

 ICE PYRAMID: (II.B.) — A mound of ice on a glacier, having stone or 



earthy debris lying against its foot. 

 ICEQUAKE: (V.C.) — The crash or concussion attending the breaking 



up of masses of ice, often due to contraction from extreme cold. 



15 



