Pond and Smith. — On the Eruption of Mt. Tarawera. 867 



out differently rocks, acidic and basic, the physical characters 

 of these rocks being as different as their chemical composition. 

 Thrown to a great height, they were caught by the wind-storm 

 and borne along by it in parallel lines from whence they 

 emanated, the acidic to the westward and the basic to the east- 

 ward, more or less admixed in the centre, but slightly com- 

 mingled on the extreme outer edge of the line. In this order 

 they advanced, and in this order were precipitated on the lauds 

 over which they passed. Coarse sand, finer particles, dust : 

 thus it was laid, in the order most to be desired by the agri- 

 culturist. So fine, indeed, is a large portion of the deposit, 

 that the elements of nutrition in it are available for vegetation 

 almost as soon as the first rains have carried it into the soil ; 

 while the particles not so exceedingly fine are already being 

 attacked by that wonderful disintegrator, carbonic acid. For a 

 moment let us glance at the basaltic lava cones in the vicinity 

 of Auckland ; and here we find the richest land, capable of 

 growing extensive crops. The more decomposed, the finer the 

 particles, the greater the amount of disintegration : the richer 

 the ground, the greater the profusion of the elements of fertility. 

 And this is the material which has been so lavishly spread over 

 the laud on the eastern portion of the district, and which is so 

 largely intermixed with the acidic matter which has fallen over 

 the western. That this rock in its unbroken, uudecomposed 

 form, is nearly valueless for plant life we can learn, by turning 

 to the basaltic floes and cinder deposits of Eangitoto ; but even 

 there, in the few gullies where rain has washed the dust, and 

 given depth of friable soil for plants to live in, where will we 

 see a richer profusion of vegetation ? The result of this down- 

 pour over so large an area need not dismay us, but rather give 

 cause for rejoicing that, in the majority of instances, a richer 

 soil has been added than formerly existed ; and so lightly and 

 finely has it fallen, that the winter rains will not have passed 

 before it will have been washed into the soil to invigorate the 

 new vegetation and improve the pastures, except in close 

 proximity to the scene of the eruption. Even here we have 

 shown that these deposits are capable of supporting vegetation. 



Probable Cause of the EnqMvn. 



To hazard a theory for so stupendous a cataclysm without 

 first obtaining the most complete data on which to build, would 

 appear reckless and unscientific ; but the amount of data already 

 accumulated, and the certainty that many mouths must elapse 

 before a complete investigation of Tarawera and Eotomahana 

 can be made, prompts us to advance a theory based on known 

 laws, the working of which has been a source of wonder and 

 attraction, and of world-wide interest, centring in Eotomahana. 

 Here, as we are well aware, rose the beautiful terraces of Te 



