Second Meeting: 24th June, 1910.
Present: The President (in the chair), and about fifty others.
New Members.—Rev. R. I. Coates, J. Fitzgerald, R. Grant, J. King, J. Snodgrass, and J. P. Thomson.
Papers.—1. “Tarawera and Rotomahana soon after the Eruption of 1886 and Twenty-three Years later,” by Mr. H. Hill, B.A., F.G.S.
In this paper the author compares the appearance of the Rotomahana district as known before the eruption and soon after the eruption, with the present appearance.
He visited the devastated area soon after the eruption, and, in company with Mr. Blythe, the officer in charge of road-construction, inspected the rift in Tarawera, the earthquake flats towards Pareheru and Tikitapu, the sites of Wairoa, Rotomahana, Waimangu to be, and the scarcely known Wai-o-tapu Valley, where they christened the Primrose Terrace. These are described, the desolate dull grey of the country, and the yawning, hissing, steaming abyss which took the place of the beautiful Rotomahana and its terraces, being then very impressive.
Stones, cinders, ashes, and sand came from the volcanoes, but only bluish-grey mud seems to have come from the Rotomahana crater.
Destructive effects seemed wanting to the south of the ridge separating the drainage-areas of Rotomahana and Wai-o-tapu, hardly any trace of eruption being noticeable in the latter place.
The country before the eruption was described by the Rev. Mr. Chapman (“Missionary Record,” 1838); Dieffenbach (1841); Rev. W. Colenso (“Tasmanian Journal of Science,” vol. i); Hochstetter (1859), whose map, published in 1863, is the only authoritative one of the pre-eruption time known to the writer; Domett (in “Ranolf and Amohia”), Trollope, and Froude.
Since the eruption Rotomahana increased from 25 acres in August, 1886, to 5,600 acres in 1893, and rose from a level of 565 ft. to 985 ft. It is now about 7,500 acres in extent. It seems to be fed by underground springs as well as by the ordinary drainage-water.
River-basin formation can be well studied in the district.
The country is now fairly well covered with vegetation, lichens, acacia (used here for firewood), grass, clover, fern, Epilobium, Gaultheria, Veronica, Dracophyllum, and tutu being mentioned as noticed.
2. “The Taupo Plateau,” by Mr. H. Hill, B.A., F.G.S.
This paper is an account of the formations met with between Napier and Taupo along the coach-road, and an explanation of the way in which the surface of Taupo district has been altered. Of two diagrams accompanying the paper, one shows the beds lying alongside the road, and the other Lake Taupo with its more important geological features.
Starting from near Napier, the appearances of limestone, conglomerate, shingle, sand, fossiliferous sand, and pumice are noted. Titiokura Hill is of Miocene beds. At Taurangakuma are Maitai slates, and thence to Tarawera slates and sandstones prevail, intrusive volcanic rocks appearing near Tarawera; beyond are rhyolites. Sandstones of Otumakioi are similar to the Permian of England. Piki-o-kiko-wera is of volcanic rocks.
On from Rununga are lavas and pumice terraces. Volcanic mounds and crateral lakes are noticeable. The Rangitaiki River rises in such lakes. Trachytes appear, and sandstones top the low hills at the north of the Kaimanawa Mountains. Peat lignites, 9 ft. thick, are exposed in the Rangitaiki bed, and these are overlaid with pumice. The country here seems to have been covered by a series of lakes. Down the river are remnants of an immense crater.
Thirteen miles from Taupo is a ridge which seems the eastern side of a great Taupo crater.
The alteration in the drainage-areas of Taupo district and of Hawke's Bay by the eruptions of Taupo, Rotokawa, and Pihanga volcanoes is explained. The effects of earthquake-action round Taupo are discussed, and Maori lengends are quoted to support the views put forth.
The Institute expressed its sense of the services rendered by Mr. Hill in past years, and wished him a pleasant time during his coming visit to England.