194 



THE GEOLOGIST. 



All the New Zealand hot-springs, like those of Iceland, abound in silica, and 

 are to be divided into two distinct classes, the one alkaline, and the other acid. 

 To the latter belong the solfataras, characterized by deposits of sulphur, and as 

 never forming intermittent fountains. All the intermittent springs belong to 

 the alkaline class, in which are also included the most of the ordinary boiling 

 springs. Sulphurets of sodium and potassium, and carbonates of potash and 

 soda are the solvents of the silica, which, on the cooling and evaporation of the 

 water, is deposited in such quantities as to form a striking characteristic in the 

 appearance of these springs. 



To enter more deeply into the theory of these phenomena would be out of 

 place here. It may be, however, well to mention that numerous facts prove 

 tliat the action which gives rise to the hot-springs is slowly diminishing. 



Ere long these hot springs will probably be visited by many travellers, not 

 only for the sake of their beauty and interest, but also for the medicinal virtues 

 they ha-f e been proved to possess. Already many Europeans have bathed in, 

 and derived benefit from, the warm waters at Orakei-korako and Rotomahana. 



There is an interesting legend current among the natives in reference to the 

 origin of these hot springs. The legend, as told by Te Heuheu, the great 

 chief on the Taupo lake, is the follo^ving : — " The great chief Ngatiroirangi, 

 after his arrival at Maketu at the time of the immigration of the Maories from 

 Hawaiki, set off with his slave Ngauruhoe to visit the interior, and, in order to 

 obtain a better view of the country, he ascended the highest peak of the Ton- 

 gariro. Here they suffered severely from cold, and the chief shouted to his 

 sister on Whakari (White Island) to send him some fire. This they did. 

 They sent on the sacred fire they brought from Hawaika, by the taniwhas 

 Pupu and Ta Haeata, through a subterranean passage to the top of Tougarii-o. 

 The fire arrived just in time to save the life of the chief, but poor Kgauruhoe 

 was dead when the chief turned to give him the fire. On this account the hole 

 through which the fire made its appearance — the active crater of Tongariro — 

 is called to this day by the name of the slave Ngauruhoe ; and the sacred fire 

 still burns within the whole underground passage along which it was carried 

 from Whakari to Tongariro." 



This legend affords a remarkable instance of the accurate observation of the 

 natives, who have thus indicated the true line of the chief volcanic action in 

 this island. 



Having described the older and more extensive volcanic phenomena of the in- 

 terior. Dr. Hochstetter proceeded to notice the later phenomena of volcanic 

 action in the immediate neighbourhood of Auckland. 



The isthmus of Auckland is completely perforated by volcanic action, and 

 presents a large number of true volcanic hills, which, although extinct and of 

 small size, are perfect models of volcanic mountains. These hUls, once the 

 funnels out of which torrents of burning lava were vomited forth, and after- 

 \vards the strongholds of savage cannibals, are now the ornaments of a happy 

 land, the home of peaceful settlers, whose fruitful gardens and smiling fields 

 derive t heir fertility from the substances long ago thrown up from the fiery 

 bowels of tlie eartli." 



_ Dr. Hochsi r1t (>r's geological map of the Auckland district shows no less than 

 sixty points of volcanic eruption within a radius of ten miles; the variety of 

 which, together with the regularity of theii' formations, gives very great 

 interest to this ueigiibourhood7 The newer volcanic hiUs round Auckland are 

 dist inguished from the older ones in the interior, not only by theii* age, but by 

 the dilViM-cnt character of their lava, the older being trachytic, while the Auck- 

 laiul are all basaltic. Tlie ditlcrence between trachyte aiid basalt consists in 

 the miuerals of which llic rocks are composed. Trachyte is composed of a mix- 

 ture of glassy IVlspar (sanidin) and hornblende ■ obsidian and pumice-stone are 



