Correspondence — Mr. J. J. H. Teall. 137 



of Tarawera, and two or three miles furtlier south Lake Rotomahana, 

 the spot where the famous Pink and White Terraces existed. Before 

 the recent eruption there were no craters on Mount Tarawera, the 

 form of which was a ridge, appai'ently due to denudation. 



Shortly after midnight on the 10th of June a series of tre- 

 mendous explosions took place from various parts of the Tarawera 

 ridge, and columns of steam were thrown up with quantities of red- 

 hot stones. The whole mountain appeared as if on fire. A column 

 of steam was then sent up from near Okaro far to the west, and, 

 finally, a great explosion took place in Lake Kotomahana, and steam 

 rushed forth to a height exceeding that of the columns from Tarawera. 

 These eruptions from the plain were not accompanied by any red- 

 hot stones; the ejecta were of much lower temperature. The 

 principal eruption, accompanied by violent earthquakes and loud 

 noises of various kinds, was over by 5*30 a.m., and the mountain 

 craters ceased to be active within twenty-four hours, but steam with 

 some stones and mud continued to issue from the Rotomahana and 

 Okero craters for several days, and steam has ever since been emitted 

 from Rotomahana. 



The results of the eruption in the form of fissures on Mount 

 Tarawera, the change of Rotomahana from a lake to a crater of 

 larger dimensions, with precipitous walls, the formation of a new 

 lake between this crater and Tarawera, and the formation of a 

 number of small craters about Okaro, were then briefly noticed The 

 materials ejected were composed of augite-andesite, and rhyolites, 

 both compact and vesicular. The mineral structure and distribution 

 over the surrounding country of various forms of pumice, scoria, and 

 ash were described, and it was shown that there was a difference in 

 the substances ejected from the mountain craters of Tarawera and 

 those from the craters in the plain at Rotomahana and Okaro, the 

 former comprising pumice and scoria, which were not thrown out 

 from the latter, and but little steam issuing from the higher craters 

 "when compared with the enormous volumes emitted from the lower 

 vents. The cause of the eruption was ascribed to the reheating of old 

 lava-streams saturated with water. This reheating was apparently 

 not due to crushing ; for, had it been so, the preceding earthquakes 

 would have been more violent, but probably to molten rock coming 

 up from below and heating the rocks near the surface. The eruptions 

 from Rotomahana and Okaro were purely hydrothermal. 



CO E. E, IB SIPOIsTZD IE InTGE 



THE LIZARD SERPENTINES. 

 Sir, — As Prof. Bonney has called in question my statement that 

 felspar occurs in the Rill serpentine, I should like to mention the 

 grounds on which that statement was based. Of course there is 

 always a certain amount of inference involved in the identification 

 of minerals under the microscope. One recognizes a number of 

 characters, and then one forms the opinion that those characters 

 indicate the presence of a certain mineral. 



