even melts heavy sheet ice that has been shoved into the protecting lane. 

 Changes in the direction of the wind are sufficient to cause floating ice 



to shift from one side of the river to the other, or from one side of a 



slip to the other. Cf. debacle, ice jam, ice run. (Figs. 102, 103.) 

 ROCHES MOUTONNEES: (II.B.j— Rounded rock hummocks found in 



glaciated regions, varying somewhat in shape according to the nature of 



the rock, its stratification or cler.vage planes, and the action of the ice. 



Usually they have a smooth, rounded back (stoss end) pointing uphill 



and a rough downhill face (lee end) which is often steep. 

 ROPAK (pi. ROPAKI): (I.A.4.f.)— A pinnacle or slab of heavy sea 



ice which has been forced to stand on edge and thus extend vertically 



upward. The crests may rise 25 feet above the surrounding ice. See 



pressure ice. (Fig. 51.) 

 ROTTEN ICE: (I.A.3.f.) — Old ice which has become honeycombed in 



the course of melting and which is in an advanced stage of disintegration. 



Rotten ice may appear black through saturation with sea water. (Thin 



sheets of newly-formed, very thin ice also appear black, and may easily 



be confused with rotten ice when met in the ice pack.) See winter ice, 



candle ice. (Figs. 33-35.) 

 ROUGH ICE: ( I. A.4.f.)— Pressure ice. 

 RUBBER ICE: (I.A.3.b.) — A type of sludge with an elastic quality and 



not strong enough to bear the weight of a man. See age (of ice). 

 RUBBLE: (I.B.l.b.) — Hard, somewhat spherical fragments of ice up to 



five feet in diameter resulting from the disintegration of larger ice. It 



may be either afloat or stranded on a beach. 

 SAILING ICE: (I.A.l.b.)— Scattered ice. 

 SALLYING: (V.A.) — Rolling a vessel by means of the crew's running 



from side to side in unison in order to loosen ice adhering to the vessel 



and to enable her to gain headway. Cf. heeling. 

 SALT FLOWERS: (I.A.3.a.)— Ice flowers. 

 SASTRUGI: (V.B.) — Wavelike ridges of hard snow formed on a level 



surface by the action of the wind (Fig. 107) . 

 SCATTERED ICE: (I.A.l.b.) — Ice that covers from one- to hve-tenths 



of the sea surface. See concentration (of ice) . (Figs. 2-4.) 

 SCREE: (II.B.)— Talus. 

 SCREW ICE: (I.A.4.f.) — Ice fragments in heaps or ridges produced by 



crushing together of ice cakes. This term may include ridged ice, 



hummocked ice, and rafted ice. 

 SCREWING PACK: (I.A.4.f.) — Ice cakes in rotarv motion due to the 



influence of wind and current. 

 SEA BAR: (I.A.l.f .)— Belt. 

 SEA ICE: (I.) — Ice formed bv the freezins of sea water. See ice. 



Frontispiece. Figs. 83. 85.) 



24 



