Art. XLI.—Some Caves and Water-passages in the Grey-mouth District.
[Read before the Wellington Philosophical Society, 1st July, 1903.]
In the following note will be found illustrations of the action of water in forming caves, and underground passages in two different ways, in the one by percolation from a ridge-top, and in the other by overflow from flood-waters.
The latter instance is to be found in the vicinity of Kumara, on the left bank of a stream known as Whisky Creek, which obtains its name from its flowing by the site of a raided still. Here, a few chains above the point where the track crosses the bed, the flood-waters pass into an underground passage, which, after expanding into a vault, branches into other passages. The outlets to these were not traced, but without doubt drain into the River Teremakau, which. Is not far distant. An entrance was forced through debris which almost closed the entrance, and a distance of a hundred paces was traversed, when further, progress was barred by the silting-up of this passage. Return was made to the vault, and another passage traversed for fifty paces. The descent of this was not without some difficulty, owing to sudden drops
and to the slippery nature of the bottom and sides. At this point a muffled sound of falling water was heard, when it was considered advisable to return, owing to the light of the lamp failing Daylight was reached after some trouble. The passages vary from 4 ft. in diameter to about 10 ft. high and 6 ft. wide, and bear signs of channelling action. Stones washed from the creek cover the floor in places, but do not occur in the sides.
Another passage not far distant from the above was also explored, and was interesting as marking the course of an, earlier bed of the stream. It lies about 30 ft. from the present bed, and is on a higher level. Its length before narrowing to a manhole in size is 50 paces, its depth roughly 8ft., and width 5 ft., the bottom overlaid with slippery mud. The journey to the spot is sufficiently interesting in itself to repay the trouble of the visit. Leaving Kumara, the Teremakau Bridge is crossed, evidences of gold-workings being abundant; then across the Greenstone by suspension bridge. Deep Creek (four miles), a small cañon said to be 70 ft. deep, is crossed. Thence a mile and a half by bush track, full of interest to the lover of scenery, brings one to the creek.
Ten minutes walk from the hotel at Greymouth brings one to any one of three examples of the effect of water percolating, gathering into a stream, undermining the overlying strata, and forming caves or crevices. There are others at hand also, in one of which the celebrated West Coast chief Tainui, I am told, is buried; but a description of the chief one will be sufficient for illustration. This is situated on the far side of the River Grey from Greymouth, just where the old bridge terminates. The entrance is about 20 ft. wide by 7 ft. high. Much care is necessary in looking through this cave, as the footing is unsafe, and a tumble of 20 ft. into a pool at the bottom is an experience to be avoided. On the left after entering is a passage descending to water-level, from which there proceeded sounds resembling the sharp puffing of a locomotive. The main portion extends sixty paces; after it is a passage of some length, accessible, however, only to the small boy. At different places shafts or passage-ways open into the main cave. These bring water from the hilltop above, if flax-seeds found on the sides of one tell any tale. Large blocks of strata have fallen from the roof and in turn been worn away and carried off as muddy water into the Grey River.
A study of the formation of this cave is specially interesting, enabling, as it does, an opinion to be formed of the action by which the Grey River evidently broke through the chain of hills at Greymouth, forsaking the old channel, which, according; to authoritative opinion, discharged its waters at a point seven miles distant.