xvi THE ANTARCTIC MANUAL. 
Nunatak.—A rocky hill, generally glaciated, projecting from an ice sheet, or from an 
inland ice. 
Pack.—A body of drift ice consisting of separate’pieces, and the extent of which cannot 
be seen. 
Oren Pack.—When the pieces do not touch. 
Cuiose Pack.—When the pieces are pressed together. 
Pack Ice.—The broken ice of floes driven together by wind and currents. 
Paleocrystic 8ea.—The mass of ancient floe ice packed against the land to the north of 
Greenland. 
Pancake Ice consists of small circular pieces with raised edges. In w ruffled sea the 
pieces of bay ice strike each other on every side, and so become rounded with the 
edges turned up. 
Patch.—A collection of drift ice, the limits of which are visible, in contradistinction_to 
pack ice. 
Pelagic._—Pertaining to the open ocean; removed from land influences. 
Penitentes = Séracs on Andes glaciers. 
Penknife Ice.—Described by Parry in his attempt to go north from Spitzbergen in 1827. 
In drained-off pools on the ice a columnar structure is left, the columns being 
6 inches high, increasing in July to 18 inches. When stratification of snow covering 
a floe is exposed by a newly-formed crack, the lower portion granulates, the grains 
collecting together perpendicularly and leaving intermediate air spaces. This 
Parry called penknife ice. 
Perched Blocks.—Boulders, usually glaciated, perched on other stones, as a result of ice 
action. 
Regelation — The freezing together of portions of ice which have been broken up. 
Roche moutonnée.—A boulder or portion of rock which has been rounded and smoothed 
by glaciation. 
Rotten Ice.—Old ice, partially ‘melted, and in part honeycombed. 
Sailing Ice—Ice of which the pieces are so separated as to allow of a ship sailing 
among them. 
Sallying a ship. Causing her to roll by the men running in a body from side to side, 
so as to relieve her from adhesion of young ice around her. 
Seracs.—Sharp irregular ridges or pinnacles of ice, formed in a glacier where there is a 
sudden change in the slope of the bed too slight to produce an ice-fall. 
Shearing Plane (the usnal sense of the wor!)—A plane along which the particles on 
either side undergo a displacement parallel with it. 
Sludge Ice —Small pieces of brash ice saturated by the salt water. 
Snout (of glacier).—The lower extremity of a glacier. 
Snow Line.—The line representing the level above which snow, not exceptionally pro- 
tected, remains unmelted throughout the year. 
Stream.—A drifting line of loose ice. 
Stria.—Scratches made by bits of grit frozen in ice on rock surfaces, smoothed by ice. 
Terminal Moraine.—Rock débris at the lower end of a glacier. 
Till.—Some authors restrict the term fiJ7 to material containing more or less angular 
material derived from the neighbouring valley system, applying boulder clay to 
that where the materials are derived from more various quarters and more often 
rounded—others use the terms as synonymous. 
Tongue.—A mass of ice projecting under water from a floe or an iceberg, and generally 
distinguishable at a considerable depth in smooth water. It differs from a calf in 
being fixed to and forming part of the larger body. 
bias 8ky.—The dark appeurance of the sky over open water, seen from a distance, in 
the ice. 
Young Ice.—Nearly flie same as bay ice; but applied to ice more recently formed. 
