464 Transactions. — Miscellaneous. 



been considered to belong to tbe solfatara type, as dis- 

 tinguished from the more active form of volcano. The 

 formation of the terraces at the Hot Lakes was due to the 

 action of steam, derived from water heated at a great depth 

 from the earth's surface, forcing its way through the siliceous 

 rocks at a high pressure and temperature, and carrying with it 

 an extract, as it were, of everything soluble in water of very 

 high temperature and' pressure. These matters were imme- 

 diately deposited at the surface, on the water escaping as steam, 

 slowly, and film after film. Extensive deposits of almost pure 

 silica formed in this manner constituted the magnificent terraces 

 at Eotomahana. Now that action, although not alwaj'^s so 

 beautifully exemplified as at Eotomahana, is going on at other 

 points, such as "Whakarewarewa, Kotorua, Orakeikorako, Kara- 

 piti, Wairakei, Tokano ; and no one ever expected that action 

 would suddenly become mere violent. It was now the question : 

 were we dealing with any new force, or was this merely a 

 gigantic display of the same force which up to the present time 

 had been exercised in a moderate manner, and, he believed, due 

 to the influence of lavas still retaining their original heat, upon 

 deep-seated strata saturated with underground waters ? He 

 was inclined to the latter view, or, in other words, that the 

 phenomenon was due to a sudden accession of hydro-thermal 

 activity, and not a renewed volcanic force. 



Tarawera Mountain was a most conspicuous land-mark all 

 over this country, standing up boldly above the other hills in 

 the district, and very similar in appearance to Horohoro, which 

 was the southern termination of the plateau-topped ridge extend- 

 iug from Cape Colville to this point. It was composed of a rock 

 called trachyte breccia, a volcanic rock consisting of mudstone, 

 cementing huge masses of trachyte and porphyry rock, and 

 there was but little doubt that it was of submarine formation, 

 and altogether antecedent to the superficial volcanic rock. 

 V. Hochstetter considered that the Tarawera Mountain also 

 belonged to this older formation. This is not quite correct, 

 because its composition is of diff'erent origin. Seen from Tara- 

 wera Lake it showed great precipices of columns like those at 

 the Giant's Causeway in Ireland, but composed of obsidian, 

 or unannealed natural glass ; and in every respect Tarawera 

 resembles ni structure the island called Tuhua, or Mayor's 

 Island, in the Bay of Plenty. Now, it Avould have been a very 

 different thing if Tarawera had belonged to the older formation, 

 which must have been quiescent for an incalculably greater 

 period than the recent. If we considered it a mountain of the 

 recent formations, it would be much easier to understand how 

 the energy may have given one last dying kick ; and that, in the 

 opinion of the speaker, when the matter is fully investigated, 

 would prove to bo the source of the whole disaster. 



