THE LAKES 21 



appear to be interpolations in its general geological scheme. It has 

 been shown that the least unlikely theory accounting for their presence 

 is one of land subsidence. Their original depths have been inferred 

 from erosion of the contiguous countryside by floods and landslips. 

 Facts have been adduced making it appear probable that the diminu- 

 tion in size of Tutira lake, otherwise than by deposition of mud and 

 silt, has been accomplished by an extremely rapid process. Lastly, its 

 future has been sketched, and, barring human interference, its eventual 

 annihilation. 



