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Geological and other Reports

Wellington, October 24, 1861

Wellington, October 24, 1861.

Sir,—At a time when considerable interest is felt with regard to the mineral resources of the Colony and Province, I have the honor to report the results of a geological tour which I have lately made in the Wairarapa and East Coast country, in the hope that my observations may be of some interest to yourself and to the public.

As a preliminary, it is necessary to make my remarks intelligible, that I should tabulate the rocks already known to exist in the above named tract of country; and having been kindly favored by Mr. Triphook of Napier, about two years ago, with a geological section of the rocks in the Province of Hawke, it will be desirable first to put down his list, as the same series of rocks extends to the country I propose to describe, and then to add to them those rocks which I have discovered.

Mr. Triphook's list of rocks in the Province of Hawke, in a descending series—



Fossiliferous limestone, marine fossils, 500 to 800 feet thick.


Crystalline sandstone gravel waterworn, unfossiliferous, 300 to 500 feet thick.


Seam of lignite (9 inches thick.)


Argillaceous indurated shale, fossiliferous.

Metamorphic or altered rock, probably Silurian.

5.Hard, green, gritty sandstone, unfossiliferous.

With the exception of the nine-inch seam of lignite (which I have heard rumours of in the Wairarapa, but have not seen) all the above named rocks extend to this part of the island.

The additions I propose to make to Mr. Triphook's series are—


Recent formations.—Deposit of travertin formed and still forming at various points on the east side of the Wairarapa, from streams charged with carbonate of lime. This deposit may be particularly remarked at Mr. M‘Masters’ station, Te Pura Pura, where I found some beautiful specimens of encrusted ferns. I also observed the same formation at Hautotara.


A raised beach extending round the coast.


I next propose to divide the tertiary gravel into two strata, to facilitate their description. An upper stratum of coarse gravel and an under stratum of fine light red gravel. The latter may be seen capping the argillaceous shale between Wangamoana and Tekopi, and both gravels are found above the shale on a river terrace at Hautotara. Where the coarse gravel forms the surface of the ground, which it does in some parts to a great extent, the soil is naturally poor.


The next addition is a series of stratified rocks, composed of flagstones, limestones, &c., which I first found resting, highly inclined, on the flanks of the metamorphic rocks, between Mr. Barton's station and Teawaiti (Mr. Riddiford's). These rocks are of totally different mineralogical character from the tertiaries already mentioned; but as I was unable to detect any fossils in them, during a cursory search, interrupted by rain, a further investigation will be necessary to form an opinion as to their geological age. To the north of Teawaiti, I observed these rocks dipping from an anticlinal axis both inland page 2 and seaward; and on one range alone I counted five different strata, each of great thickness, inclined and showing a bold serrated edge against the sky as the point of each stratum projected. These rocks ought to be carefully examined to ascertain their age and character, and as I found indications of coal, viz., a very thin seam of that mineral, in a conglomerate rock of the series, it is just possible that we may here find the representatives of the carboniferous rocks lately discovered by Mr. Haast in the Province of Canterbury. There is every reason to suspect that this series will prove to be either secondary or palæozoic. On a line parallel to the East Coast, and perhaps at a distance of ten miles from it, a number of precipitous and jagged summits are found. These hills are called taipos by the natives, and are, I am told, held in superstitious dread, as the supposed dwelling places of evil spirits. They seem to be composed of stratified and tilted sandstones, although we may find that they are broken into by igneous rocks.

The last addition which I would make at present to the list of rocks is of great geological interest. It is a true igneous rock, a hornblendic rock, which I found on Mr. Beethams' run, not in situ, but in fragments in the bed of the Upoko Ngaruru; from the decomposition of this rock ironsand is deposited, and in it Mr. Haast has discovered a speck of gold with the microscope. I would here mention that a fossil cetacean is to be seen in the bed of the Upoko Ngaruru, washed out of the argillaceous shale, and that as the floods are rapidly destroying all traces of it, it would be worth the attention of the Provincial Government to secure for the Museum as much of the skeleton as now remains.

The hornblendic rock of the Upoko Ngaruru I believe to be the first igneous rock yet discovered in the Province of Wellington, exclusive of those rocks of the Taupo country, whose pebbles are brought down the Whanganui and adjacent rivers.

Having added the above mentioned rocks to our series, I will now give a table of the rocks from Wellington to the East Coast, premising that it must be open to amendment or addition as the progress of observation and discovery proceeds.

Tabular view of strata from Wellington to the East Coast, in a descending series:—



Travertin—Found at Te Pura Pura, Hautotara, and other points on the eastern side of the Wairarapa valley.


Raised beach—Extending round the coast. This we may venture to call “recent,” subject to future correction.



Fossiliferous limestone—Found on Maungaraki range, at Hautotara and other parts of the Eastern Coast range.


Coarse crystalline sandstone gravel, unfossiliferous—Largely developed in the Wairarapa, and on the western slope of the East Coast ranges.


Fine red gravel—Seen at Wangamoana, Hautotara, &c.


Indurated clay, fossiliferous.—Perhaps the name should be shortened into “blue clay.”—Exposed at Wangamoana, and very extensively found in the East Coast ranges—Contains the cetacean of Upoko Ngaruru, marine shells, imbedded trees, &c.

Possibly secondary or palæozoic.


Series of stratified rocks of the East Coast.—Found highly inclined on the East Coast.

Probably silurian.


Metamorphic or altered rocks.—These form the Rimutaka and Tararua ranges, including all the mountainous country round Wellington, rocks extending northward from Cape Palliser, &c.



Hornblendic Rock.—Found in the bed of the Upoko Ngaruru, one of the sources of the Pahaua.

To sum up—The metamorphic rocks fill a large area at the base of the series. They compose the Rimutaka and Tararua ranges, with all their spurs and offshoots as far as is yet known; they appear again cropping out on the hills on Mr. Bidwill's run, where there is probably a line of fault; they are seen between Wangamoana and Tekopi, underlying the tertiary clay; and to the eastward of Mr. murcha's homestead they rise into mountains presenting their hard surface at Cape Palliser as a buttress against the sea, and apparently there forming the mass of the mountains for a considerable distance to the northward. Whatever metals may be found in this part of the country will doubtless belong to the metamorphic rocks (except perhaps ironsand). As specimens of native copper appear to have been found in the East Coast range, a search for ores of copper in any of the metamorphic rocks may prove successful. The rocks of Cape Palliser appear to be identical with those of the main range, therefore if gold is found in one range, it may be expected in the other.

The stratified rocks of the East Coast may be searched for coal and lime and other minerals and useful rocks, including flagstones, grindstones, &c., and the tertiary limestone may yield a useful lime. Bog iron ore, and what is called in Scotland muir band pan, page 3 are found in the gravel. They are of little interest, except as being identical with the same substances in Great Britain.

A few words on the general dip and strike of the strata may be useful. The metamorphic rocks are so bent, broken, and twisted, that it is difficult to give an opimon as to their prevailing dip, but the tilting action on the newer formations seems to me to have principally acted along a line from Cape Palisser to the northward, parallel to the East Coast. From this line, all the tertiary strata that I have observed dip gently to the westward, and on the other side of this line the supposed secondary rocks dip at a high angle to the eastward, and, if I am not mistaken, are north of Teawaiti broken through by this line of upheaval, and then dip both east and west.

Trusting that the above rough generalizations may serve as a guide, and lead to a more correct knowledge of the geological structure of the Province,

I have the honor to be,

Your most obedient servant,
James C. Crawford.

To His Honor I. E. Featherston,
Superintendent of the Province
of Wellington.