PALEOCRYSTIC ICE: ( I. A.3.e.)— Pressure ice, usually more than 

 ten years old, well weathered, and irregularly heaped and tumbled. The 

 type locality is the Lincoln Sea. 

 PAN: (I.A.2.) — An abbreviation for pancake ice. 



PANCAKE ICE: (I.A.2. or I. A.3.)— Pieces of newly-formed ice usually 

 between one and six feet in diameter. The raised rims and the circular 

 appearance are a result of the almost constant rotation and collision of 

 the cakes against one another. Small cakes up to about 18 inches in 

 diameter are occasionally called lily pad ice. (Fig. 29.) 



PATCH: (I.A.l.f.) — An irregular cluster of floating ice fragments of 

 any concentration. Cf. belt, tongue. (Fig. 10.) 



PERMAFROST: (II.B.) — Permanently frozen ground. Any soil or 

 even bedrock, irrespective of its texture, degree of induration, water 

 content, or geological character, in which the temperature has been con- 

 tinuously below freezing over a period of years (varying from several 

 to perhaps tens of thousands) is considered as permanently frozen 

 ground. 



PERMANENT ICE FOOT: (I.B.I. a.)— An ice foot that does not melt 

 completely during the summer months. 



PIEDMONT BULB: (I I. A3. a.)— Expanded foot ice. 



PIEDMONT ICE: (II.A.3.C.)— An ice sheet formed by the coalescence 

 of ice spreading out from two or more wall-sided or valley glaciers 

 over a comparatively level plain at the base of the mountain slopes 

 down which the glaciers descended. Piedmont ice may be partially 

 afloat. See glacier, land ice. (Fig. 77.) 



PINNACLED ICEBERG: (II.A.5.a.)— An iceberg that has been 

 weathered and eroded in such a manner that spires or pinnacles extend 

 vertically upward from the main body. See iceberg. (Figs. 87, 88.) 



PLATE ICE: (I. A3.)— Pancake ice. 



POCKET: (I.C. lb.)— Blind lead. 



POLAR CAP ICE: ( I. A3. e.)— Polar ice. 



POLAR ICE: (I.A.3.e.) — The thickest and heaviest form of sea ice 

 more than one year old. Cf. winter ice. (Figs. 30-32.) 



POLYNYA (pi. POLYNYI): (I.C.l.c.)— Any sizable sea water area, 

 other than a lead, encompassed by ice. See water opening. (Fig. 66.) 



POOL: 



(1) (I.C.l.c.)— Polynya. 



(2) (l.A.4.g.) — A depression on sea ice filled with water. See puddle. 

 PRESSURE ICE: (I.A.4.) — Ice having any readily observed roughness 



of the surface. Flat ice is the result of undisturbed ice growth and 

 development, whereas pressure ice refers to a disturbed growth and 

 development. Such disturbed development is the result of wind, current, 

 tide, and/or temperature change. Types of pressure ice are: Rafted, 



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