44 



TUTIRA 



the valley bottom. Amongst them no doubt are endless cracks and 

 gaps through which water escapes perhaps to reappear at lower levels 

 of the stream itself, perhaps to reissue elsewhere as fountains. There 

 are also in its bed minute intermittent whirlpools that alternately suck 

 and cease to suck its waters down. 



One other form of erosion remains to be described. The sum-total 

 of its effects is so puny that perhaps I should apologise for its inclusion, 

 yet there is a fascination in its strange rapid action. It is an operation 

 readily to be appreciated by those who have attempted to water a 

 steeply-sloping garden bed, dust-dry and in finest tilth. About the 

 bases of bare scarps the unhealed scars of hillside slips quantities of 



the finest dust accumulate in dry seasons. 

 On these miniature skrees of powdered soil 

 fall the first great drops of a western 

 shower. The dust slope can neither retain 

 the drops nor instantaneously absorb them. 

 Striking the slope they gather earth particles 

 in their downward course. While thus in 

 motion, as if by miracle, they change from 

 liquid to solid. Metamorphosed first into 

 ashen-grey and then into brown balls, these 

 earthen pilules, preserving their shape but 

 changing their substance, race madly down- 

 hill, bound downhill, no longer clear drops 

 from heaven, but minute circular solid globes 

 of soil. With a faster fall of raindrops the 

 process ends perforce ; the dust-heap be- 

 comes a mud torrent. 



Frost and wind have played but minor 

 parts in the transfiguration of the run. The 

 former on wintry mornings has accelerated the weathering of the cone 

 area by elevation of their sand surfaces on upright spicules of ice, 

 the latter by blowing abroad the desiccated dust. Doubtless also 

 frost has contributed to the disintegration of other surfaces ; speak- 

 ing generally, nevertheless, it is water which has moulded the run to its 

 present shape. 



Shrinkage of the station has been compared to the decay of a 



" No longer clear drops from 

 heaven, btet minute circular 

 solid globes of soil." 



