THE CHARTOGRAPHERS OF THE STATION 



197 



heavy rains, not the least sudden is a blunder into an unnoticed 

 earth-bubble. 



Other curious though unimportant physical creations are mud- 

 banks, built on the margin of the lake by passing floods. The 

 waters of the lake, feet above the normal, blown violently from the 

 direction of the gale, are piled up in big waves against the mass of 

 flood -water pouring off the valleys. At the junction of these con- 

 tending forces, a narrow width of calm, or at any rate currentless, 

 water is produced. Beneath its line of quiescence mud and silt 

 are quickly and copiously precipitated, until, with cessation of the 

 storm, and a -rapid drop in the level of the lake, a submerged mass 

 or mound of mud is revealed, which, becoming grass-bound and solid, 



After flood. 



may exist for years, a long hog-backed monument to some mighty rain- 

 storm. 



Not one of these surface changes, directly or indirectly brought 

 about by stock, can be considered other than insignificant ; yet their 

 aggregate has sufficed to alter the surface of Tutira in an almost in- 

 credible degree. Although, maybe, that change has been of greater 

 interest to the writer than to his readers, at any rate it will have 

 enabled them to realise the cumulative result of trivialities. 



