A copy of the draft warrant is submitted by the Department of External Affairs to the Commonwealth Relations Office for its unofficial approval. Once this has been obtained the Warrant is submitted for Royal approval by the Governor-General. Before this can be gazetted, however, the new seal must be received in New Zealand so that its impression can appear on the Royal Warrant.

In all probability the first Public Seal of New Zealand was sent out in 1841, as Governor Hobson wrote a dispatch of 6 August 1841 to the Colonial Secretary acknowledging its receipt. The seal was designed by Benjamin Wyon, R.A. (1802–58) who was appointed Chief Engraver to the Seals on 10 January 1831. The design depicted Queen Victoria in treaty with a group of Maori chiefs. The second seal was also designed by Benjamin Wyon and was approved by Queen Victoria in February 1848. It was dispatched with the New Ulster and New Munster seals on 1 April 1848 and was received on 8 September. This seal, which was made of silver, remained in use until 1880 when, because of wear, it was decided to replace it with a steel one. The second seal was sent to Her Majesty in Council who defaced it in November 1881 and returned it to New Zealand.

Later seals were withdrawn on the death of a sovereign and replaced on the accession of a new ruler. Exceptions to this rule were at the death of George V and the accession of Edward VIII.

The third seal was engraved by Alfred B. Wyon, Chief Engraver of Her Majesty's Seals, son of Benjamin Wyon. With screw press, copper counters, and box, it cost £90 6s. It was received in early August 1881 and was in use until late 1903. The fourth seal was ordered on 17 February 1902 and received in November 1903. The fifth seal was dispatched from England on 29 July 1912, received on 1 October 1912, and defaced on 15 November 1939. The sixth seal came into use on 15 November 1939 and was ordered by a Royal Warrant, published on 28 July 1959, to be defaced on the arrival of the seventh seal, which is in use at the present time.

The Public Seal is reserved for documents which require the signature of the Governor-General. These include the following categories where its use is obligatory: (a) Proclamations; (b) Crown grants (now very rare); (c) Warrants of appointment of members of the Executive Council and Ministers' warrants of appointment; (d) Appointments of the Chief Justice and of Justices of the Supreme Court; (e) Appointments of Royal Commissions; (f) Warrants for appointments to Army, Navy, and Air Force.

Documents which merely require ministerial signature are, if necessary, sealed with the common seal of the particular Department concerned.

When the Public Seal was first sent to New Zealand in 1841, it was used with the Governor's signature on all dispatches to the British Government, on grants of waste land, and on letters patent designating local body areas.

(Hippocampus abdominalis).

This quaint little fish is not uncommon around seaweed-covered rocks in shallow water throughout New Zealand. It grows to 5 or 6 in. in height and is usually greenish-grey mottled with brown. The body is narrow and strongly cross-ridged on the sides. The resemblance of the head to that of a horse is most marked, and the likeness is further strengthened by a well-formed neck and prominent chest. The tail, however, is coiled and used for attachment to seaweeds, where the little fish awaits its tiny crustacean victims, which are sucked into its tubular mouth.

by Arthur William Baden Powell, Assistant Director, Auckland Institute and Museum.

Sea urchins are echinoderms, to which group belong also the starfishes and the beche-de-mer sea slugs. The most distinctive structure of an echinoderm is an elaborate water-pumping system which activates numerous feelerlike processes known as tube feet. Echinoderms have a network of calcareous plates embedded in tissue and muscle. In the sea urchins these plates are fused as a mosaic to form a rigid shell, the exterior of which is usually furnished with movable spines.

Typical of our local sea urchins are the common sea urchin or sea egg (Evechinus chloroticus), greenish to purplish, and densely spinose on a flattened circular “shell”, 4–6 in. across, which is light greenish when the spines are removed.

The heart urchin (Echinocardium australe), very thin shelled, 1–2 in. across, is found buried in mud from shallow water to about 16 fm.

The cake urchin or snapper biscuit (Arachnoides zelandiae), is a five-segmented shelly disc found in fine sand at entrances to harbours. The broken-up triangular segments are commonly cast up on beaches.

by Arthur William Baden Powell, Assistant Director, Auckland Institute and Museum.

(Ctenophore).

The sea gooseberries or “comb-jellies” are related to the jellyfish family, though they are zoologically a group quite distinct from common jellyfish and Portuguese man-of-war. In appearance and size they are very like a completely transparent gooseberry. Between the upper and lower “poles” are eight meridional rows of “combs” consisting of tiny cilia (resembling hairs) which beat rhythmically and propel the animal through the water. It is very common in New Zealand waters, easily captured by means of a plankton net, and its characteristic method of movement makes it an interesting study when placed in a tank or jar of water.

by Richard Morrison Cassie, M.SC.(N.Z.), D.SC.(AUCK.), Senior Lecturer in Zoology, University of Auckland.

The sea floor may be conveniently divided into three regions: the Continental Shelf (to about 100 fm deep), the Continental Slope (from 100 to 2,000 fm), and the abyss or deep sea (from 2,000 to about 5,500 fm). While each region can thus be generally characterised, the boundaries between them are not abrupt, but consist of gradual changes in the physical conditions and in the animals present. In each region there are four main physical factors that control the distribution of the animals, namely, the temperature and salinity of the surrounding water, the nature of the sediments on the bottom, the depth, and the type of food available. These factors vary from place to place and so, consequently, does the population of animals. The variation of these factors is most marked in the shallow waters on the Continental Shelf and becomes progressively less as the water deepens. Hence animals in shallow water are more restricted to particular regions than those in the deep sea. Sea-floor animals have definite tolerances to physical conditions and definite food requirements, and their distribution is dependent to a great degree upon these factors.

Sea-floor animals may also be broadly classified according to the nature of their food and their method of feeding. First, there are those animals which are herbivorous, living on seaweeds or plant material. These animals are mainly confined to the shallow near-shore regions where the seaweeds live. Most of these animals are molluscs such as sea snails and periwinkles, chitons, limpets, and similar types, and include the common paua, Haliotis iris. Some deep-water echinoids (sea urchins) have been found feeding on plant debris washed out by rivers, but none is yet known from New Zealand waters.

Other benthic (bottom living) animals live attached to rocks and stones or in the sediments and get their food by filtering the tiny planktonic animals or plants out of the surrounding water. The sponges and sea mosses, the mussels, and the rock and mud oysters of Auckland and Foveaux Strait are typical of these filter feeders. Other filterers live in burrows in the mud or sand for protection and send tubes to the surface to suck in sea water to filter for food; the pipi and toheroa (Amphidesma ventricosum) are representatives of this group.

Another group includes the solitary corals, and related hydroids, the sea anemones, bryozoans (sea mosses), and crinoids or feather stars. Some of these are individual animals and some (the bryozoans) are colonies or multitudes of separate animals; the animal is firmly attached to rock or other firm foundation and feeding is accomplished by sweeping the surrounding waters with arms or tentacles. Still another group of animals comprises those that search the mud or sand where they live for small animals or remains. These forms include sea urchins, such as Echinocardium cordatum (the common heart urchin), sea cucumbers or holothurians, and brittle stars (Amphiura rosea is one widely distributed species), as well as many bivalve shellfish and worms. Some animals are carnivorous, moving over the sea bed preying upon others; the oyster borer, Lepsiella scobina, lives upon a diet of rock oyster; the olive shells (Baryspira), starfish, such as Coscinasterias calamaria, and octopuses all actively hunt for food.

Many other animals are scavengers, eating any dead animal remains that they find. Most of the crabs fall in this category, along with hermit crabs, some shrimps and prawns, and other crustaceans, such as amphipods and isopods.

Those animals growing up from the sea floor or moving over it are known collectively as the epifauna, while those living buried beneath the surface can be grouped together as the infauna.

The majority of the examples given are from those commonly known on the Continental Shelf. In contrast, the fauna of the deeper seas is not well known, and collections from the New Zealand Continental Slope and abyss are as yet very limited. Some of the animals occurring in these regions also occur on the Shelf, but many are restricted to the deeper sea. Generally, animal life is somewhat less abundant in the deep sea than in the shallow marginal Shelf. In the deeper sea below the levels at which light can penetrate and plants can grow, herbivorous animals are, naturally, almost completely lacking; hence the animals feed chiefly on microscopic plank-tonic life, on organisms living in the sediments, or are carnivores and scavengers. In some groups there is a tendency for the animals to grow long legs to enable them to move more rapidly over the soft sediments and so obtain more food.

Animals from the very deep sea have not been extensively collected in the New Zealand region. The conditions in this region are often very similar throughout the world, and many deep-sea animals are known to occur throughout the Pacific Ocean. The Danish research ship Galathea collected some of our abyssal animals in the very deep Kermadec Trench to the north-east of New Zealand, many of the animals being new to science. In general, the deep-sea animals are not of peculiar types, but fall into categories similar to those of the Continental Slope. They are, however, somewhat more sparsely distributed.

by Donald George McKnight, New Zealand Oceanographic Institute, Department of Scientific and Industrial Research, Wellington.

References to New Zealand sea-floor animals, although numerous, are very scattered and some difficult to obtain. Two books by A. W. B. Powell, Native Animals of New Zealand and Shells of New Zealand, are very handy for the beginner. From here, one may refer to many useful papers in the Transactions of the Royal Society of New Zealand and to work published by the various New Zealand institutions working in the marine sciences.

New Zealand Shelf sediments consist basically of gravel and sand near the open coast, sand and mud in various proportions on the central part of the Shelf and near river mouths, and gravel, sand, and mud in various proportions near the margin of the Shelf and in constricted channels where strong currents are active, for instance, Cook Strait and Foveaux Strait. The near-shore sediments and those on the central part of the Shelf are evidently being deposited at the present day, but the relatively coarse sediments near the Shelf margin and in constricted channels were deposited during an earlier phase of sedimentation, being late Pleistocene to early Flandrian in age. The areas where these older sediments are found are zones where no present-day deposition is taking place.

The derived pebbles and sand which make up the Shelf sediments of New Zealand consist mainly either of very resistant rocks like greywacke, or of types whose great abundance outweighs their relatively non-resistant character, such as the Taupo rhyolitic pumice. Metamorphic fragments are abundant off some parts of the South Island coast. Formations of Tertiary age consist mostly of non-resistant rocks which are rapidly broken up by erosion and transport, and are rarely found as recognisable fragments on the Shelf. In a few areas, for example, Foveaux Strait, shells and shell fragments make up a considerable proportion of the sediment.

The sediments on the New Zealand Slope, over most parts of the continental borderlands, and in the nearby ocean basins, consist mainly of terrigenous mud and foraminiferal ooze in various proportions. The foraminiferal component predominates at a considerable distance from land, and here the sediment is whitish in colour; near the coast, on the other hand, the percentage of terrigenous mud rises, and the sediment takes on a pink, brown, or green tinge, depending on the colour of the terrigenous admixture. South of the latitude of Auckland the colour is usually pale green, but north of this latitude pale pink or brown colours are typical. On the higher parts of the continental borderlands, particularly in the case of isolated banks, coarse shell-fragment sand tends to occur instead of foraminiferal muds.

The sediments of the Chatham Rise are unusual in several respects. The typical sediment is a foraminiferal sand or silt, but there occur places where cobbles and pebbles of igneous, metamorphic, and sedimentary rocks are present in and below the finer material. These pebbles may have been rafted on to the Rise by icebergs during the Pleistocene. There also occur pebbles of phosphatised limestone, and small granules of phosphatic glauconite.

by Henry Moir Pantin, B.A.(CANTAB.), PH.D.(CANTAB.), New Zealand Oceanographic Institute, Department of Scientific and Industrial Research, Wellington.

Most of the sea bed is covered by sedimentary deposits, although there are numerous areas, particularly on the Shelf and on the Oceanic Ridges, where outcrops of solid rock occur. Except for limited regions near the coast, where the sea bed is within reach of divers, direct examination of the sediments and rock outcrops by a geologist is not possible without the use of a diving machine such as a bathyscaphe. Such a machine is very expensive and, although samples could be collected by remote control, the crew themselves could see the rock or sediments only through the window of the observation sphere. In practice, geological information may be gained by a series of methods which cover most of the information which can be obtained with a bathyscaphe, and a great deal which cannot. These methods include collecting samples of the sea bed, submarine photography, and geophysical methods, mainly seismic, gravity, and magnetic surveys.

Rock outcrops on the Shelf occur most frequently near the coast and around the outer edge of the Shelf. The rock types may include igneous, sedimentary, or metamorphic varieties, and are generally similar to those on the nearby land mass, although the sedimentary rock types tend to be more common than on land. Apart from the outcrops, the Shelf is covered with sediments of various types. Gravel and sand predominate around the intertidal zone, and may also be found in limited zones near the Shelf margin. Over the remainder of the Shelf, the sediments consist of sand and mud in different proportions: the ratio of sand to mud tends to decrease away from the coast, but may locally increase near the edge of the Shelf. The material of the sediments is normally composed of erosional debris from the land mass, but in the tropics large parts of the Shelf may be covered with coral reefs and calcareous sediments derived from these. Opposite the mouth of large rivers, sandy and muddy river-derived sediments may spread right across the Shelf, especially when the sediment supply is abundant. In these cases, there is usually a delta projecting out some distance across the Shelf. In glaciated regions, the Shelf may have a hummocky surface due to glacial erosion and to the deposition of till and other glacially derived sediments; the latter usually contain a high proportion of pebbles and sand.

Deposition on the Shelf takes place in several ways. Near the coast sediment is churned into suspension by waves and washed out across the Shelf by wave-generated currents and turbulence; this outward movement of sediment is assisted by the “turbidity effect”, that is, the tendency of sediment-laden water near the coast to move down the gradient of the Shelf by virtue of its effective density, which is greater than that of clear sea water. This is a weaker form of the same process that produces “turbidity currents” on the Slope and in submarine canyons. The wave-turbulence effect becomes weaker away from the coast, and this also applies to the turbidity effect as far as the Shelf margin. The weakening of these two processes away from the coast allows the deposition of sediment on the upper and central Shelf, but near the Shelf margin there occur tidal and oceanic currents which tend to wash away recent sediment and prevent deposition, thus allowing rock outcrops and areas of older sediment to appear. In addition, tidal streams may be strong locally in constricted channels, and correspondingly effective in preventing present-day deposition of sediment, as in central parts of Cook Strait.

The essential form of the Shelf is believed to be due to erosion and deposition governed by “wave-base”, that is, the depth below sea level at which erosion or sediment transport ceases to be effective. This depth is normally different for erosion and for deposition, and it depends greatly on the nature of the available sediment and the underlying bedrock. Nevertheless, the present depth of the Shelf is too great for it to have been controlled entirely by present-day sea level. The Shelf was probably formed mainly during the later phases of the Pleistocene glaciation, when the ice-caps of the world were much larger than at present. A significant proportion of the water in the oceans was locked up in these ice-caps, and sea level is believed to have fallen by 200–300 ft on several occasions during the Pleistocene.

Slope sediments are predominantly mud, which may be greenish, bluish-grey, yellow, red, or black, depending on the source of the material and conditions of deposition. These muds grade outwards into one or other of the various types of oceanic sediment. Some submarine canyons contain predominantly muddy sediment, but others contain sand, and outcrops of rock occur along many canyon walls.

Transport by currents belonging to the main system of oceanic circulation is more significant than on the Shelf. Wave-generated turbulence is weaker, and less sediment is directly stirred up by waves, but the steeper gradients facilitate turbidity flow. In some areas, moreover, particularly within submarine canyons, the gradient is sufficient to allow the occurrence of submarine landslips. A heavy storm on the Shelf, producing a mass of water heavily laden with sediment, or a big submarine landslip, may in fact generate a self-propagating “turbidity current”, in which the downward velocity of the turbid water is sufficient to keep the contained sediment in suspension. These turbidity currents usually flow into and down submarine canyons, and are believed to be responsible for the sandy sediments sometimes found in the canyons. It is probable, in fact, that some of the canyons have actually been eroded by turbidity currents, although others can be shown to represent river valleys submerged by local subsidence of the earth's crust.

In the Ocean Basins, the distance from land is so great that land-derived sediment accumulates very slowly and consists almost entirely of clay. As a result, the main character of the sediment in many parts of the ocean is determined largely by the presence of the accumulated skeletons of planktonic micro-organisms, which frequently grow in great profusion. The Foraminifera, which have calcareous shells, are abundant in temperate and tropical latitudes, and form a large proportion of the deep-sea sediment known as “foraminiferal ooze” (also called “globigerina ooze” after one of the dominant groups of Foraminifera). This covers the sea floor for wide areas around New Zealand. At depths below about 2,500 fathoms, however, the calcium carbonate of the shells becomes soluble in sea water, and so the shells cannot remain in the sediment. Only the land-derived clay is left, and the sediment is known as “red clay”, although its colour is usually pink or brown. In some parts of the tropics, notably in the Pacific, the siliceous organisms known as Radiolaria grow in great abundance, and form the sediment known as “radiolarian ooze”. Diatoms (minute siliceous plants) are abundant in both Arctic and Antarctic waters, and form extensive areas of “diatomaceous ooze”, although here the situation is complicated by the presence of glaciers and ice-caps; melting icebergs introduce large quantities of rock-flour and glacial erratics into the sediments of the surrounding seas.

Core samples from the Ocean Basins occasionally show layers of sand intercalated with the typical deep-sea oozes. These sands are believed to have been deposited by exceptionally powerful turbidity currents, which still had sufficient velocity after reaching the base of the Slope to travel and spread out for several hundred miles over the ocean floor.

Rock outcrops on the Oceanic Ridges are mainly submarine lava flows, which are nearly always composed of basalt; this is also by far the commonest type of lava on the oceanic volcanic islands.

On isolated submarine banks, the sediment may consist predominantly of gravel, sand, or mud, depending on the depth of the bank, its distance from shore, and the strength of currents in the area. There is a general tendency, however, for sediments on banks to contain a high proportion of calcareous biogenetic material, which is composed mainly of shells and shell fragments in the coarser types of sediment, and Foraminifera in the finer-grained types. Two unusual types of sedimentary material which form under rather special conditions are phosphorite, which takes the form of brownish granules or nodules composed of a calcium phosphate mineral, and glauconite, a potassium iron silicate which occurs in the form of small granules with a green or greenish-black colour. Glauconite and phosphorite both tend to occur in places where sediment is accumulating very slowly, such as continental borderlands or submarine banks and ridges situated on the outer Shelf or on the Slope; the Chatham Rise is an excellent example of this kind of environment. These minerals form on the sea bed or just within the sediment, which is usually a sand or mud containing numerous Foraminifera.

The bathymetry of the sea floor around New Zealand provides examples of most of the main types of feature. The coast is surrounded by the Shelf, which varies in width from one area to another. The narrowest portions of the Shelf are found off the east coast between Kaikoura and Cape Kidnappers where the width varies from less than 1 mile up to about 15 miles, and off Fiordland where the variation is from 1–4 miles. Around other parts of the coast, the Shelf is much more extensive, being generally 10–40 miles wide, while in western Cook Strait and south of Stewart Island the width increases to over 100 miles.

The gradient of the Slope varies a great deal between different areas, there being a broad correlation between the steepness of the Slope and the narrowness of the Shelf. In the Fiordland sector, the Slope is very steep, with a maximum gradient of about 1 in 4; the Slope is also relatively steep off the east coast between Kaikoura and East Cape, although in this sector there occur a number of submarine ridges and basins which locally reverse the general gradient. Apart from these two areas, most of the Slope is relatively gentle, but locally there occur steeper zones, for instance, the upper part of the Slope east of Otago Peninsula.

Several submarine canyons cut the Slope between Banks Peninsula and East Cape. The largest of these are the Pegasus Canyon (north of Banks Peninsula), the Cook Strait Canyon, and the Madden Canyon off Porangahau. The Cook Strait Canyon has an unusual shape as compared with most submarine canyons in other parts of the world, with its numerous branches and other irregularities, while the Madden Canyon with its great headward expansion is also exceptional. A group of smaller submarine canyons occurs east of Otago Peninsula.

Between Kaikoura and East Cape, the Slope flattens out rather abruptly at 1,500–2,000 fathoms into the Hikurangi Trench, a feature of low relief which is replaced by the much deeper Kermadec Trench to the north-east. In the sector between East Cape and North Cape, the Slope descends slowly and somewhat irregularly into the South Fiji Basin and the Havre Trough, while it flattens out at intermediate depths opposite the prominent Kermadec Ridge and the less conspicuous Colville Ridge. West of Fiordland, the Slope flattens out rapidly at about 2,000 fathoms into the wide and flat Tasman Basin. North-west of the North Island, and south-east of the South Island, the Slope fades out at shallow or intermediate depths and passes into two large continental borderlands. That to the north-west comprises the Lord Howe Rise, New Caledonia Basin, and Norfolk Ridge, while that to the south-east comprises the Chatham Rise, Bounty Trough, and Campbell Plateau. All of the continental borderland features are of major dimensions, and the majority cover an area equal to or greater than the North or South Islands. Along their outer margins they grade downwards into the adjoining ocean basins.