EGMONT'S ACTIVITY,

Auckland Star, Volume LXII, Issue 88, 15 April 1931, Page 6

EGMONT'S ACTIVITY,

The finding of a Maori or Polynesian cooking place buried under volcanic material naturally deposited must open up an unexpected field for further research regarding the. antiquity of man in New Zealand and also for gauging the approximate date of Egmont's last eruption. The theory advanced by your correspondent "Abcona" as to the last eruption of Egmont being "prior even to the event of man on this planet" is a little far distant, for have not researches into the history of fossil man shown him to have 'been as such as far back as the time geologically contemporaneous with that of Taranaki's birth, viz., the Newer Pliocene? The probabilities also of the oven having been buried under a shower of ash originating from Mount Ngauruhoe or elsewhere in the Tongariro belt is also rather 'remote, "but surely an examination of the material covering tho oven would soon settle that question.

A shower of ash from Ngauruhoe of sufficient extent and density as would bury anything on the slopes of Mount Egmont until the present date must necessarily have left some trace over the intervening country, but no such trace is to be found. The intervening country is to my observation completely free from any such deposits. The only volcanic material derived from the central volcanic mount of the Tongariro system is that which has been water-borne by the streams which flow from that area. Streams which do not drain from that area but which may have their sources quite near to it 'but wholly among scdementary rocks have no sign of pumicc or volcanic material in their valley terraces. Nor is there to be found any sign of volcanic material on the hilltops or on the saddles where one might well expect it to have accumulated. This is a point which early impressed me and one which I took every occasion to verify, for it is strange that although showers of ash which are indubitably derived from Tongariro's system have extended so far to the north, north-east, east and south-east direction, yet to the west they have, in spite of the frequency of winds from the east, extended not further than a few miles, at least in any lasting quantities. The furthest extension of ash in this direction I found at about twenty miles S.S.W. and about twelve miles west of Iluapchu; here the material feathers out and becomes indistinguishable.

The shower which this material represents appears to be contemporaneous with a vast shower which lias extended over the Northern Ruahines and easterly over the Kaimanawas. It is of post-glacial age and had its origin, I should think, in Mount Kuapeliu. To the north-west there appears to have been a shower across in the Tc Kuiti-Miaroa direction, but this is of a different character, and considering how seldom we have wind from the south-east this shower is remarkable. The evidence shows perhaps that the eruptioris were not quite so frequent as might be imagined, for they seem to have escaped the easterly gales, which are quite frequent. Truly there is little evidence on Mount Egmont of any recent discharge of ash, or, indeed, does it appear to have ever discharged so voluminously as has the Tongariro system. The ejecta is richer and more fertile to plant life than is that of Tongariro. This, combined with the heavy rainfall of the district, would soon allow it to be covered with vegetation, of which a plentiful supply was never far distant. An eruption which might be sufficient to cover a Maori oven on one side of the mount might at an equal distance on the other be very light, as, being engaged by a stiff wind from the-.west, the shower would move as in a swathe to the east. Although such might be the case, there occur no signs of havoc or destruction of the forest, which appears to ascend to about an even height on all sides of the mount in a state of freshness and maturity. Above this the subalpine flora forms a dense mat and combination that must have taken a very long time for its establishment.

Not so, however, the precincts of the Tongariro belt. Here we see many desert places which extend well into the forest zone, and, with the significant exception of a few scattered patches of marram grass and toitoi, the surface is still drifting sand. These bare places occur to the eastern and south-eastern sides of the mountains, or the side 011 which most of the erupted ash seems to have drifted. We are prone, in these matters of the past of which we have no written record, to assign their happening to time as geologically measured, and whilst we use the term "recent" in a geological sense we usually do not relate it with events which are' practically of to-day and of yesterday. Who in the future, geologist or otherwise, would, in the absence of written records and knowledge of the facts, assign the correct date for the raising of the coastline at Napier, or to the eruption of Tarawera ? Indeed, how much of the -events of which we assimilate such a vivid knowledge per medium of the printed page would be remembered in a few generations' time without the preservation of printing or' writing? Consequently the past events, of the earth anterior to authentic and written record must rely for their interpretation on the process of reasoning and tentative explanation. —J. ATTWOOD.