198 



PLATE C. THE PINNACLED ICE OF M'MURDO SOUND. 



FIG. 1 (Map B). From a photograph by L. C. BERNACCHI (Be. 75, ^-plate) ; taken 

 on the floating Pinnacled Ice of M'Murdo Sound, Feb. 8, 1902. 



FIG. 2 (Map B). From a photograph by L. C. BERNACCHI (Be. 71, ^-plate), of the 

 same, Feb. 8, 1902. 



These pictures represent phases of extreme weathering on the surface of old 

 and dirty glacier-ice. The ice-sheet is afloat, but almost stagnant ; it has its origin 

 at this point mainly in Kcettlitz Glacier, and runs thence northward in M'Murdo 

 Sound for some twenty miles. Owing to the great quantity of morainic debris 

 which it carries on its surface, there is a considerable amount of thaw during the 

 height of summer, i.e. in December and January. 



The dry beds of thaw-water streams which have undercut the ice in every 

 direction are here represented. The black heaps consist of sand and gravel, and 

 this material, when distributed in a thin layer, quickly melts out the ice beneath. 

 Where, however, it is more abundantly deposited, it affords a permanent protection 

 to the ice upon which it lies. 



See also Plates XCVI. to XCIX. ; and for further details, see Scott, Voyage 

 of the 'Discovery,' vol. i., p. 209 ; and Ferrar, Nat. Hist. Rep., vol. i., pp. 15, 80, 90. 



