32 E. C. ANDREWS 



strained in this connection. It is only necessary to assume that ice 

 acts somewhat as a viscous body; i. e., that its surface should show 

 a gradually curving fall from summit to baselevel. Thus we get 

 increased velocity with increased volume of ice, as with ordinary 

 streams, and the capacity for work exhibited by the more quickly 

 moving mass is not related by a simple ratio to that performed by the 

 more slowly moving one. 



' Fig. 7.— Wet Jacket Arm. Note the partial truncation of spurs resulting in 

 precipitous facets facing the Sound. 



The same idea of wonderfully increased efficiency as regards 

 cutting, transportation, etc., is seen also during the convergence of 

 two ice-masses into a canyon of very little greater width than either 

 of the two feeders. 



TOPOGRAPHIC CONDITIONS OBTAINING IN SOUTHWESTERN NEW 



ZEALAND 



I. We have a much dismantled plateau in the area under con- 

 sideration (Figs. I, 2, and 7). Great convergence of these plateau 

 remnant valleys to the later canyons is often observable. 



