Art. XLII.—Notes on some of the Diatomaceous Deposits of New Zealand.

By John Inglis.

Lake Summer, North Canterbury.

About ten or twelve years ago Mr. John Russell, then of Lake Sumner Station, observed on the margin of a tiny rill, on his run, on the hill slopes, on the southern side of the lake, and about two hundred feet above the present water-level, some dry whitish lumps of earth, which he brought to Christchurch and submitted to the inspection of Dr. von Haast and me. Dr. von Haast informed him of its diatomaceous character, and as I had the opportunity of visiting the neighbouring station shortly afterwards, I arranged with Mr. Russell to visit the spot. I found the vegetable mould and deposit cut into by the rill to the depth of two or three feet, laying the latter bare. The terrace land falls back at this point from the lake, and taking an easterly sweep, at an elevation of about three hundred feet, towards the “Big Brother” Mountain, allows space for Lake Katrine, and opposes a barrier to the discharge of Lake Sumner, with which it is connected by a narrow channel, in that direction. The waters of Hurunui River pass through Lake Sumner, and discharge themselves between the farther side of the “Big Brother” and the mountains on the Nelson side of the river, and through a huge clay bank. It appears therefore probable that this deposit has been made at a long past period of the lake's history, when its level was much higher than it is at present.

The deposit is very rich in many fine forms, and two species new to science have been found in it. On various occasions I have supplied samples of the earth, and some of them have found their way into the hands of English diatomists, and through their instrumentality the new forms have been described.

Triceratrum trifoliatum, Cleve, n.s.

This form is unique and very remarkable. It is figured and described in the “Royal Microscopical Journal” for June, 1881, by Dr. Stolterforth, under the name Hydrosera tricoronata as obtained “from a sub-peat freshwater deposit, North Canterbury. The exact locality not known.” I have ventured to suggest its lacustrine origin.

The description given by Dr. Stolterforth is as follows:—

“Filamentous. Front view of valves nearly quadrangular, showing four ridges and a deep central depression, distinct connecting band; side view trilobate, each lobe having three projections or minor lobes. The lobes are finely dotted, no regular markings on the central hexagonal portion.”

Professor Cleve has also described the species shortly prior to Dr. Stolterforth, hence the name attached.

Plate XXIX., fig. 1, a side view, b front view.

• Triceratium trifoliatum.

• Nitzchia spectabilis.

• " amphioxys.

• Navicula cardinalis.

• " major.

• " viridis.

• " commutata.

• " divergens.

• " hemiptera.

• " placentula.

• " firma var. amphigomphus.

• " " var. subampliata.

• " bacillum var.

• " elliptrica.

• Gomphonema constrictum.

• " clavatum.

• Stauroneis (Pleurostauron) fulmen.

• " " frauenfeldii.

• " " javanicum.

• " " acutum.

• " phœnicenteron.

• Melosira orichalcea.

• Cymbella scotica.

• Pinnularia punctulata.

Wainui, Akaroa Harbour.

This freshwater deposit is extensive and so pure as to render it suitable as an article of commerce. The following species have been already found:—

• Epithemia ventricosa.

• " musculus.

• " proboscidea.

• " longicornis.

• Synedra ulna.

• Odontidium mutabile.

• " var.

• " tabellaria.

• Pinnularia nobilis.

• Cymbella affinis.

• Melosira punctata.

• Eunotia arcus.

Dunedin.—Green Island.

This is a freshwater deposit taken from a railway cutting near Green Island, and is chiefly composed of—

Eucyonema cæspitosum.

Cust Valley, North Canterbury.

I discovered a small pocket of this sub-peat deposit, about five years ago, which consisted chiefly of the doubtful genus Amphicampa, and was

described by me, in vol. xiv. of the Transactions of the New Zealand Institute, as Himantidium maskellii. Mr. Brightwell describes a specimen from Melbourne under the name Eunotia eruca^* The leading diatomists of England now include Amphicampa and Himantidium under the genus Eunotia. Subsequently I found other deposits in the same swamp, and note the species found as follows:—

• Eunotia eruca.

• " bidens.

• " undulatum.

• Stauroneis cruciculum.

• " phœnicenteron.

• Pinnularia major.

• Gomphonema constricta.

• " viridis.

• Synedra radians.

• Surirella linearis.

• Orthosira orichalcea.

• Epithemia longicornis.

• " turgida.

Amberley, North Canterbury.

On the property of Mr. Alex. Broadfoot, Seaview, at a point on the top of the terrace where until lately there was a spring of water, I found a considerable deposit, and in the peat swamp below I found the following fresh-water species:—

• Stauroneis (Pleurostauron) fulmen.

• Eunotia eruca.

• " triodon.

• Melosira punctata.

• " var.

• Synedra vulgare.

• Pinnularia acrosphœnia.

• Eunotia (Himantidium) bidens.

• " arcus.

• " undulatum.

• " pectinale.

• Gompbonema constrictum.

New Brighton, near Christchurch.

A fresh-water and possibly brackish-water deposit was laid bare by the formation of Paynton's road through the swamp. I have been able to identify the following forms:—

• Pinnularia major.

• Navicula munda.

• " didyma.

• " elliptica.

Macintosh Bay, Banks Peninsula.

On the hill-slopes of the bay, a visitor noticed after rain that the water trickling from the side of one of the spurs left a white deposit on the grass, some of which was gathered and placed in my hands for examination. I endeavoured to get the position of the deposit fixed, but hitherto without success. I found, however, the following diatoms in the very minute gathering which I received:—

• Cymbella cuspidata.

• Nitzchia amphioxys.

• Gomphonema constrictum.

• Synedra ulna.

• Surirella minuta.

• Navicula cuspidata.

• " sphæophora.

• " amphibæna.

• Achnanthis exilis.

Whangarei, Auckland.