682 Transactions. — Geology. 



Between 1859 and 1880 no attempt seems to have been 

 made to ascend any of the mountahas that were held to be 

 tapu by the Natives, and which inchided the whole of the 

 volcanic group. In the latter year, however, Messrs. Maxwell 

 and Beetham reached the south peak, known as Parae-te-tai- 

 tonga. There they built a cairn and left several small coins 

 as mementoes of their visit. Since, the mountain has been 

 crossed on several occasions by Government surveyors and 

 others, and the topography of the mountain is now fairly well 

 known. 



As pointed out by Hochstetter, the mountain is an enor- 

 mous truncated cone, with ridges running for miles to the east, 

 north, and south like the gnarled roots of an ancient forest- 

 tree. Towards the south the mountain presents a much 

 steeper face than to the north, east, or west. On the east the 

 mountain is most broken and denuded, and has much smaller 

 snowfields than are met with on the west and south-west. 

 Long, sloping ridges occur here, and these actually form the 

 water-parting between the rivers flowing to the north and 

 south respectively. The forest-lands run close to the snow- 

 line on the west and partly on the south ; but only clumps of 

 stunted Fagus panax and scrub are found along the east and 

 north-east portion of the mountain. Euapehu is separated 

 from Ngauruhoe by a valley varying from a mile to two miles 

 in width. The Tongariro group is situated within an area of 

 desert and desolation, which, from its height in comparison 

 with the surrounding area, may be likened to the top of an 

 immense dome, which flattens in the direction of its rim. 

 Here and there transverse corrugations appear to break the 

 general arrangement, as in the case of the Kaimanawha and 

 other smaller ranges ; but these do not alter the dome-like 

 structure which the North Islaiid presents, with Euapehu and 

 Tongariro as a centre. 



The country immediately surrounding the cones has a 

 varying height from 4,800ft. to 3,000ft., and it is made up prin- 

 cipally of pumice and lava-flows from the mountains. Here 

 and there along the western side of the group are numerous 

 conical hills made up of volcanic lavas, but having no crateral 

 hollows or basins such as are usual in cones from which lava 

 has issued ; and it may be assumed that traces of lava-flows 

 will be found along the whole line of country which separates 

 Euapehu and Egmont. On the east side of the group no such 

 cones are found, and the country as far as the Kaimanawha 

 Eange is composed of a grit and pebble pumice mixed with 

 coarse material of many rock varieties similar to what were 

 found in the vicinity of Eotomahana soon after the eruption. 

 The clinkers found on the Eangipo Desert in clumps here and 

 there differ from all the volcanic material I have seen else- 



