THE GEOLOGICAL SURVEY.

Press, Volume LXIII, Issue 12593, 8 September 1906, Page 8

THE GEOLOGICAL SURVEY.

The publication of the first bulletin of the geological survey as reorganised by Dr. Bell liae been awaited with, more than ordinary interest. This Department has been in a comatose condition for & number of years, and needed eoxoe etimulus *o quicken it into acttive and energetic life. This has been given to it by the young Canadian geologist appointed by tho Government to supervise and direct ite operations. Coming ffrom a continent which thoroughly believes in the application of science to industry, where problems ane attacked with tho freshness and freedom characteristic of a young and vigorous community, it was to bo expected that he would give a new impetus to the etudy of tho geology of the colony. Hia first bulletin has amply justified our anticipations. The most conspicuous feature of former geological reports lies been their unintelligibility by those who are not professional geologists. A great deal of valuable information hns been obtained, but it is obscured by a mass of complicated detail, which needs time and patience to unravel. They have therefore been very uninviting to the general reader. Besides this, "they have been too controversial in character, laying too much etress on the correlation of series in different parts of the country., and paying too little attention to tiio economic poesibißfciee of individual formations. As far as the

j public are concerned, it is much more Importent to know the exten* and value of a pettJoulair coal area then to oompar© ita geological date vn& a eimilar ono in another part of the owrntry. Thie last can only be done when the isolated areas have been thoroughly studied. » The new evidently believes in describing a particular district thoroughly, without any present attempt at ©orrelaftion- No doubt with greater experience of the local condition* he will be able to draw mono definite conclusions about the etrategraphical sequence of some of oux involved formations. It is evident from hie report that he eets about his tack with an open mind, and ie very ready to appreciate the good work of the pioneers of geology in this country. Dr. Bel has begun, by dividing the whole co l <mj into a number of districts called quadrangles, in each of which there is come important geological question to settle. For instance, he has divided this province into three, which he calls the Waimakariri, the Ashburton, and the Pukaki quadrangles, but theee ere reserved for future examination, and are hardly referred to in the bulletin now issued. This deals with the Hokitika sheet of the North Wcstland Quadrangle, that ie, with the area roughly bounded by the Teremakau, Taipo, and Hokitika rivers, and extending from Lake Kamieri to the Upper Wilborforce, the latter really being in the Waimaklriri Quadrangle, but dealt with more easily ia this report. The results given embody a year's work by the officers of the survey, and give promise that the ■whole colony will, in the course of time, thoroughly_examined, though it will etitainly take a quarter of a century to report on all parts, if, the • present rate affords an accurate indication for tho future. It seems probable that the Hokitika anta was chosen not only from the fact that it was in the lafe Premiere own constituency, but also because it is one of the most interesting geological localities in the colony, and it was hoped that valuable economic discoveries would be made to justify the existence of the department. The following points are mentioned by Dr Bell in his introduction as being specially worthy of investigation:—(l) the exiat- ' enoe or non-existence of a mother xedf whence tho aUnvial gold l of the district was derived (2) the discovery of new auriferous leads to take the place of fhose now exhausted, (3) the investigation of the coaMfcieasures, and (4) the seaTc3i for metalliferous veins andi minierals of economic value. After , pointing out the problems to be.attacked, the writer gives a brief 'history of the district as well as accounts of the methods of gold mining, of the communications, flora, fauna, soil, and climate—in fact just such information as would be of us© to anyone in another counttry who wished to understand the land that was being described geologically. Dr Bell thus writes nob only for tfoo people in New Zealand, but for the world , in general. In this respect ho follows the lead of the meet , advanced surveyors of America; for their report* contain detailed accounts of features not usually thought requisite for a geological report. They embrace such subjects as topography, terrestrial magnetism, forestry, which really have an intimate connection with the physiographic geology of'a country. It seems a matter for regret that a botanist of standing was not attached to Dr BeH'e survey party, as a.full botanical report of tho area wonldi be of great scientific and oconomio value and could have been carried out with little additional cost. It is to be hoped that this want will bo satisfied before the other sheets of this quadrangle are dealt with. ' After the general introduction, the next feature of the report which calls for special notice is the account of the physical geography of the locality, In this Dγ Bell has applied with success the methods of the American School of Phyeiographens. He draws special attention to the mode o$ formation and the history of the Southern. Alps, to tho Wainihinihi pene-plain, the work of the glaciers in modifying the valleys, the t directions and changce of direction of th* rivers, the formation of\ho,lakes and of the coastal plain. This chapter should be read with interest by all who are engaged in teaching the geography of our colony, and should be disseminated more widely than geological bulletins usually are. If Dr. Bell carries out his work in other parts of the colony in the same way, his reports ought to prove veritable mines of information •for those who would correctly appreciate the means by which the surface features of this country have been moulded into their present form. One error, we notice, however, in this part of the subject. It seems to us that the word "piedmont," as applied to a glacier, ie not ueed with its proper meaning. It ia doubtful whether this type of glacier has ever existed in New Zealand, unless, perhaps, during the time of their greatest extension, when the piedmont plains were partiilly covered by ice. The piiroly geological problems are dealt with "in the main part of tho report in a thoroughly scientific manner. Tbo different series are described as they occur, in this locality, with no attempt as yet to compare them with similar rocks oleewbore, but their economic possibilities are fully considered. This, we think, is a most valuable feature of the bulletin. It eeeme rather unfortunate that one of the series was named after Like Kanieri, without adequate explanation, as the name has been earmarked for another series differing altogether from it in character and date. Dr. Bell has been fortunate to find in position tho mm*

eral nephrite, commonly called greenstone. This is the finrt time it hae been discovered in this locality in the solid rock, though a deposit was found a few*months ago near Milford Sound an a similar belt of country, and, we believe, now supplies a good deal of the mineral bo extonsirely used. The rocks which form the matrix of the mineral are called the pounamu series, after the well-known Maori name for greenstone, and they also contain deposits of serpentine and steatite, as well as rubies and traces of platinum. These may ultimately be of some economic value. Other minerals have been found in the area, but not in any promising quantities, although building stones of great beauty and good quality are common. The report disposes of the existence of the mother reef, from which the alluvial gold has been derived, and accounts for it by supposing that the rocks of the mountain range containing traces of cold have been pounded up by glaciers in former geological ages, and the gold from thorn has been concentrated by the action of water in old river beds, and forms tho present surface leads. Hopes are hold out that deep loads may bo discovered under tho blue bottom which underlies the present surface leads. A very large number of quartz reefs •were examined and tested, but very few showed payable gold, and after a careful examination of the ' Wilberforce country Dr. Bell says that in only two or three oases do the claims already taken up chow a "fair prospecting proposition."Good specimens are undoubtedly obtained, and picked samples give a large assay return, but a high percentage of the reefe* of tho district are absolutely worthless. It -will bo inferred from reading tho whole report that the economic possibilities of the area; aro not very promising. In conclusion, we must note the attractive manner in which the report is generally -written, and tho excellent photographs, which show the difficulty as well as the beauty and grandeur of the country which formed tho scene of operations.