ORIGIN OF ICE-FLOES II9 



between the ice-fields, the narrow lanes of water which, now 

 opening, now closing-, afford most perilous and difficult ways 

 to the higher north. I'inally, where the western shoulder of 

 Greenland and Grinnell Island narrow the passage which 

 leads into the Arctic Sea, the ice is so firmly held together 

 that it has never been found sufficiently fissured to afford 

 room for the passage of the smallest boats. Thence on to 

 the long-sought but apparently inaccessible Pole, the sea is 

 covered with a connected sheet of ice, the upper surface of 

 which is exceedingly rough and hummocky, so that it is 

 impassable for sledges. The vast region covered by this 

 sheet of floe-ice, which probably has a depth of one hundred 

 feet or more, has been termed the Pakeocrystic Sea, or the 

 Sea of Ancient Ice. It is clear that its envelope of frozen 

 water is but a more consolidated area of sheet or floe accumu- 

 lations — in other regards exactly like the fields which float 

 out of Davis Strait and move down the coast of Labrador 

 until thev invade the Straits of Belle Isle, and through this 

 channel penetrate into the Gulf of St. Lawrence or crowd 

 into the inlets of northern Newfoundland. 



It is evident that the origin of this floe-ice is as follows, 

 viz.: In the long winter of high latitudes the surface of the 

 sea, wherever it is not affected by the warm waters of the 

 south, freezes so that a considerable depth of ice is made. A 

 single winter will often accumulate it to a thickness of ten 

 feet or more. In the short summer this ice only in part 

 melts away, and the next season adds still more to it. When 

 the sheet breaks up into separate fields, these masses, often 

 square miles in area, are set in motion by the tidal currents 

 or the strong winds ; they collide with each other and with 

 the shore, and by these accidents the cakes of ice are shoved 



