The oceans cover nearly two-thirds of our planet and are its last great frontier for natural resources. The depths of the oceans and the ocean floor itself were of little interest until the middle of the last century when the first scientific deep-sea surveys were undertaken. The Challenger expedition nearly a hundred years ago discovered the existence of phosphorite and manganese dioxide concretions on the ocean floor, but these remained of purely scientific interest for many years. Although offshore mining of petroleum dates from 1899 and although undersea deposits of hard minerals, such as iron or coal, were mined even before the turn of the century by driving shafts and tunnels from the adjoining land, the seabed and its subsoil did not acquire much economic significance until after the Second World War. Even then, political, economic and legal interest was confined to the land underlying the shallow waters of the continental shelf; virtually the only practical use of the land underlying deeper waters was considered to be as a support for submarine pipes and cables. As late as 1956 it was possible for the International Law Commission to state with regard to the ocean floor that "apart from the case of the exploitation or exploration of the soil or subsoil of a continental shelf ... such exploitation had not yet assumed sufficient practical importance to justify special regulation."

The last few years, however, have witnessed a spectacular change in attitudes. On the one hand, there has been an increasing realization of the importance of ocean resources to man's future; and on the other, rapid technological progress has resulted in the discovery of vast mineral resources on and under the ocean floor and has made these resources accessible and exploitable for a variety of purposes. Until comparatively recently man relied on the weighted line and laborious dredging for his knowledge of the seabed. We now have underwater photography and television, the echo-sounder and a variety of sophisticated seismic and other devices, such as scanning sonar, which can conveniently provide us with a precise image of the ocean floor and some indication of its geological structure. Thus man has probably been able to acquire more knowledge about the deep seas and the ocean floor in the past fifteen years than in the preceding two thousand years.

THE WEALTH OF THE SEABED

ALTHOUGH the oceans are vast and although our knowledge of the submerged land beneath them is still fragmentary, there is no doubt that the value of known ocean resources has increased at least in proportion to our knowledge of the marine environment and to the advance of technology. Hence there is legitimate expectation that the 90 percent of the ocean floor that is unknown will be revealed to contain resources as valuable as those already discovered.

Estimates of offshore reserves of petroleum, natural gas and sulphur are soaring. In 1950 natural gas reserves under the United States continental shelf were estimated at 50 trillion cubic feet; in 1965 they were estimated at 150 trillion cubic feet. In 1947 world offshore petroleum reserves were not believed to exceed 1 trillion barrels; in 1966, they were estimated at 2.5 trillion barrels. This excludes the more recent discovery of enormously rich petroleum deposits under the arctic continental shelf of the Soviet Union and a major oilfield reported to contain an estimated 5 to 10 billion barrels of petroleum off northern Alaska.

Beyond the geophysical continental shelf, the sediments of the ocean floor are believed to contain 100,000 trillion tons of calcareous ooze, which could be used for the manufacture of cement, and some 100 trillion tons of siliceous ooze which could be used in the manufacture of insulating brick, as a filler, as an absorbent and as a mild abrasive. Ocean floor sediments also contain 100,000 trillion tons of pelagic clays containing manganese grains in concentrations up to 5 percent, and, in addition, a variety of minerals and rare earths in varying concentrations. Valuable deposits of phosphorite in the form of nodules, slabs or pellets are known to exist on the outer continental shelf, on the continental slope and on submarine banks.

Manganese nodules, a scientific curiosity until a few years ago, are the hard mineral resource which is attracting most attention at the present time. Irregularly spherical in shape, they are commonly found on the surface of the ocean floor at depths between 4,500 and 19,000 feet. Concentration and distribution of the nodules vary widely and so does their chemical composition. Maximum known metal content of the nodules has been determined as follows: 57.1 percent manganese, 39.5 percent iron, 2.9 percent copper, 2.4 percent nickel, 2.1 percent cobalt, etc. Tentative tonnage estimates for Pacific Ocean nodules, based on a far from adequate knowledge of the extent of deposits, range from 9 to 170 trillion tons. Such quantities would meet present demand for these minerals for scores-in some cases hundreds-of thousands of years. Indeed, the manganese nodules are accumulating faster than the world (in 1960) is consuming the metals they contain.

Although we know that immense, untapped mineral resources exist on and under the ocean floor, some are likely to remain unexploited for the foreseeable future, either because there is an abundant supply on hand or because we still lack the technology for detailed evaluation of deposits and for their subsequent exploitation. However, remarkable advances have been made in the past decade. In the case of hydrocarbons, exploration wells were dug at a water depth of 70 feet in 1953; the figure is now 640 feet; and by next year, with new equipment, it may be 1,500 feet. In 1953 no wells were located more than 25 miles from land; now there are wells over 100 miles at sea. Fifteen years ago evaluation of mineral deposits lying on the seabed could be carried out only in very shallow water; now sufficiently accurate evaluations can be undertaken in depths exceeding 3,000 feet.

Exploitation techniques are not as advanced as those for evaluation. Three main techniques are used for the exploitation of mineral resources on and under the seabed: drilling, dredging and mining. Drilling for production purposes has now reached depths of approximately 350 feet and is expected to exceed 600 feet by the end of this year, as compared to less than 70 feet twenty years ago. Dredging is at present mainly limited to the exploitation of placer deposits in depths not exceeding 100 to 200 feet according to the minerals mined; this, however, compares with depths of around 30 feet in 1947. Technology for mining bedrock deposits in water deeper than 300 feet is not yet in sight.

As evaluation and exploitation of the mineral resources of the ocean floor venture into even deeper waters, technical problems multiply. The Economic Sub-Committee of the Ad Hoc Committee established by the United Nations to study the peaceful uses of the seabed beyond national jurisdiction has stated that "extrapolation of these figures [i.e. comparison of the present technological position to that of twenty years ago] would imply that another decade will be necessary to double again the depths reached at present, but it is no doubt hazardous to anticipate the rate of further progress of technology since major breakthroughs cannot be excluded."

There are several indications that major breakthroughs may be imminent. Considerable publicity has been given to the recent construction in several countries of vessels which can submerge to depths of some 9,000 feet and serve a variety of specialized purposes-scientific, recreational, rescue, ocean-engineering or military. It is believed that if present materials- high-strength steels and aluminum-continue to be used, rapidly increasing costs will inhibit extensive commercial and military intrusion into the deep sea. However, a new generation of deep-submergence vessels, in which much use is made of materials such as glass in the construction of pressure hulls, is either on the drawing boards or under construction; in addition some of the vessels will be nuclear-powered. Several of these vessels, such as the Hikino and Lockheed's DSRV are designed to operate at depths in excess of 20,000 feet. Of particular importance is the construction of sophisticated robots and low-cost submersibles capable of performing useful tasks on the bottom at great depths.

Another recent major technological development has been the demonstrated ability to adapt human physiology in such a way as to enable man to operate freely for long periods at depths at least as great as those of the geophysical continental shelf.1 Although it is difficult to forecast the potential of present techniques in view of the complex problems involved in the acclimatization of man to the ocean depths, it has been confidently predicted that by 1975 there will be colonies of aquanauts living and working on the ocean floor at depths in the neighborhood of 1,500 feet.

Thus not only the entire continental shelf and most submarine banks, but also some of the summits of the great submarine mountain ranges already appear within range of permanent occupation by man, and the technology exists or is about to be developed which will make the greater part of the ocean floor both exploitable and more conveniently accessible in the near future, possibly the next five years.2 Whether the ocean floor beyond the geophysical continental shelf can be commercially exploited within the next decade has been seriously questioned, despite the technological advances that have been made. It is said that we know too little about that vast mysterious world plunged in perpetual darkness and that even if sufficient knowledge were available the cost of exploitation would be prohibitive. Both objections are based on the situation as it is now, but I do not believe that they take sufficiently into consideration the dynamism that exists in the field.

It is true that our knowledge of the ocean floor beyond the geophysical continental shelf is fragmentary. It is also true that what knowledge we have has been acquired almost entirely within the last fifteen years and that indications point to the existence of a wide range of virtually inexhaustible mineral resources. This is likely to be a powerful spur to action. Exploration, limited and poorly funded fifteen years ago, is now proceeding at an ever increasing pace; the Inter-governmental Oceanographic Commission, established in 1960, has organized several wide-ranging and extremely successful oceanographic expeditions; more are planned. The Decade of Ocean Exploration proposed by the United States will be endorsed by the United Nations General Assembly this autumn and will certainly lead to a vast increase in our rapidly expanding knowledge.

II

Private enterprise appears confident that present exploration efforts will yield commercially valuable results. Investment in the offshore oil industry has reached $13 billion; the greater part of this, of course, has been made within the limits of the continental shelf, but in the last five years a growing proportion has been made beyond the shelf. Offshore oil- lease payments to the United States Government alone have produced more than $1.7 billion within the past 13 months for drilling rights to be exercised within the next five years; more than one-third of this sum was from leases on areas under more than 600 feet of water. It is hardly likely that oil companies would pay millions of dollars for leases unless there were reasonable prospects of successful exploitation before expiration of the lease. We can therefore reasonably expect that exploitation of hydrocarbon deposits beyond the geophysical continental shelf will start soon. Exploitation of surface deposits, such as phosphorite and manganese nodules, may lie somewhat further in the future. It is significant, however, that a phosphate lease on areas under some 4,000 feet of water has already been granted, and that there have been reports that a prototype submersible for the mining of the manganese nodules on the deep ocean floor is under construction.

The cost factor in offshore exploration and exploitation is high and the risks are greater than on the land, but known and suspected mineral resources may be worth the gamble. With regard to the oil industry, it is noteworthy that although the average offshore "dry hole" costs about $370,000, as compared to $50,000 on land, the trade magazine Off-shore said recently: "The offshore industry is standing on the doorstep of the biggest drilling boom in history. In one year, the industry has demonstrated its faith in the outer continental shelf with three record breaking oil and gas leases, as well as in vast off-shore concessions abroad."3

Various considerations are likely to intensify the pressure for the early employment of the ever more sophisticated technology available. The world is faced with a rapidly expanding population, which will require the consumption of vastly increased quantities of food, minerals and other natural resources. It is unlikely that the land alone will be able to provide for all the needs of mankind at acceptable cost; hence the vital importance of oceanic and suboceanic resources. More important in the short run may be the desire of many technologically advanced countries to correct balance-of-payments deficits or to lessen their dependence on foreign countries for petroleum, natural gas and many minerals vital to industry. An example of such considerations was the comment which appeared in the London Daily Telegraph of July 21 in connection with the discovery this year of the new Alaskan oil field: "Commercial exploitation of Alaskan oil on a big scale may be some years off," it said. "In the meantime its existence makes a handy club with which to fend off would-be blackmailers, be they political or simply after more money."

Finally, governments throughout the world are showing an increasing interest in the deep seas, the ocean floor and its subsoil-an interest reflected in rapidly rising government budgets. As late as 1956 the U. S. Government's expenditure on oceanographic research and technology was about $25 million; this year it will be $448 million despite the financial stringency caused by the war in Viet Nam, and the amount is expected to double within the next two years. Similar increases in government expenditures may be observed in the Soviet Union, France and other countries, although in absolute terms they cannot be compared to that in the United States.

The main reason for this governmental interest is military. Governments have suddenly realized the vital importance of the deep seas and ocean floor to defense. An unidentified Russian is reported to have said that the nation that first learns to live under the seas will control them, and the nation that controls the seas will control the world. There is much truth in this statement. Limited military use of the ocean floor is already being made, and there is little doubt that the major naval powers are planning to take full advantage of its strategic possibilities, within the limits of their respective technological and financial capabilities. There are many military uses, both nuclear and conventional, to which the ocean floor and its subsurface could be put. Deployment of an anti-ballistic missile system on the oceanic mountain ranges, for example, could prove an effective counter to multiple-warhead missiles aimed at land targets. The advantages are obvious: more than one strike at incoming missiles would be possible; secondly, incoming independently targeted missiles could be attacked before the several warheads separated. There are also indications that research is being undertaken on the development of mobile seabed systems either for nuclear weapons or for detection. The seabed can be used, too, for the emplacement of nuclear mines for offensive or defensive purposes.

Conventional military uses of the seabed include deployment of anchored sonar systems to detect and track vessels moving on or under the surface of the ocean, anchored navigation aids and communication facilities. Many of these devices are already available and some deployment beyond the continental shelf has already taken place. It is also possible to envisage the establishment of fortifications or fixed military installations, such as underwater submarine bases on the ocean floor. These would extend the length and range of submerged missions and thus improve the possibilities of concealment.

Improved concealment is perhaps the most important factor behind the intense interest of military authorities in the seabed. In the opaque atmosphere beyond moderate depths, even fixed military installations would be difficult to pinpoint. Silos and military installations buried in the seabed-certainly a serious possibility-would be almost impossible to identify. Thus the advantages of using the deep seas and ocean floors for military purposes to the greatest possible extent may appear compelling to the country or countries possessing the requisite technology. Yet such a course of action may have grave consequences.

For example, the successful deployment of extensive tracking devices would impair the near invulnerability of missile submarines and would consequently produce seriously destabilizing effects. Secondly, use of the ocean floor for military purposes would almost certainly lead to an immediate and rapid escalation of the arms race in the seas. The race may have already started: an informed guess is that the United States Navy is currently spending about $400 million for submarine tracking and detection devices installed on the ocean floor. An intense nuclear and conventional arms race already exists in the atmosphere, on land, on the surface, and immediately under the surface, of the seas; the addition of an arms race in a new environment, as now appears to be in prospect, would further strain the financial resources of the major powers, causing postponement of those comprehensive measures for the improvement of standards of living which are widely considered to be imperative. The disappointment of impatient expectations could increase both internal and international tensions.

When large manned military installations and permanent fortifications become feasible, it is possible to envisage an arms race degenerating into a competitive scramble by a few countries permanently to appropriate accessible strategic areas on the ocean floor without much regard to the interests of others. Permanent military installations on or beneath the ocean floor require secure protection against spying or harassment, and this could lead to the unilateral proclamation of jurisdiction over large areas of the surrounding and superjacent sea. A distinguished military expert stated last year: "Military installations are now centered reasonably close to the land mass; that will not be the case ... ten years from now. We will carve out rather large chunks of the ocean away from the land masses which we ... regard as very important to our national defense and ... we shall deny access by any other nation to the areas which we will block out." If one major power were to block out large areas of the ocean and ocean floor, it is not unreasonable to believe that other technologically advanced countries might follow suit.

Storage or deployment of nuclear weapons on or underneath the ocean floor would constitute an additional hazard to the integrity of the marine environment as a whole-an environment already threatened by the systematic large-scale dumping of the radioactive and other wastes of an increasingly industrialized world. It is clear that vigorous action by the international community is becoming imperative in the interests of all. Yet although there has been much study and discussion of the problems of ocean pollution, effective action at the international level has been lacking. The main obstacles, apart from a general lack of a sense of urgency, are fragmentation of competence and plurality of jurisdiction, both at the national and international level. Moreover, the problem is scarcely susceptible to a satisfactory solution in the present legal context where it is uncertain who, if anybody, has responsibility for the deep seas, the ocean floor and its subsoil beyond a continental shelf that is variously defined in different legislation.

III

The current state of international law is reflected in the provisions of the 1958 Convention on the Continental Shelf, which came into force in 1964. The Convention recognizes that a coastal State has sovereign rights, for purposes of exploration and exploitation of natural resources, over its continental shelf defined as: "the sea-bed and the sub-soil of the submarine areas adjacent to the coast but outside the area of the territorial sea, to a depth of 200 metres or, beyond that limit, to where the depth of the superjacent waters admits of the exploitation of the natural resources of the said areas."

At the time it was concluded, the Convention was hailed as a major achievement of the United Nations. So convinced were legal experts of its excellence that revision was made difficult; not until five years after entry into force-that is, not before 1969-can a request for revision be entertained, and even then "the General Assembly of the United Nations shall decide upon the steps, if any, to be taken in respect of such request." Unfortunately, however, the framers of the Convention were not in touch with developing technology and apparently did not conceive that the seabed could soon be exploited for military and commercial purposes beyond the arbitrarily selected 200-metre isobath.

The definition of the continental shelf, as incorporated in the 1958 Geneva Convention, has lent itself to two basic interpretations.

The first holds that the deep-sea floor, with the possible exception of areas immediately adjacent to the coasts, cannot be included within the scope of the Continental Shelf Convention. Exponents of this approach recognize the existence of a possible legal problem with regard to submarine areas situated under still undefined depths of water and at still undefined distances from the coast. They advocate either delaying the establishment of a legal régime for these areas until their utilization for military or commercial purposes forces the issue, or suggest, in the words of Northcutt Ely, that "until enough international competition and friction develop to justify the creation of some advance license system . . . recognition of the flag of the craft or other surface mechanism from which the exploration is controlled sufficiently identifies the jurisdiction which ought to have plenary control over the exploration and over the exploitation of the resources so discovered."

This interpretation of the 1958 Geneva Convention has not gone unchallenged, however, since it is in contradiction to the explicit wording of article 1(a), which states that the continental shelf extends to "the submarine areas adjacent to the coast... to a depth of 200 metres and beyond that limit to where the depth of the superjacent waters admits of the exploitation of the resources of the said areas." This would appear to mean that a coastal State may extend its effective jurisdiction over the ocean floor at ever greater depths as technical capability anywhere in the world makes exploitation possible, until eventually the midway point between it and the coastal State opposite is reached. Such an interpretation would give the powers governing such small islands as Clipperton, Easter, St. Helena, Azores or Niue sovereign rights over millions of square miles of invaluable ocean floor. It would give the United States relatively little, the Soviet Union less, and landlocked countries nothing at all.

More important than the opinion of jurists, however distinguished they may be, is the action taken by governments, which are increasingly inclined to appropriate unilaterally whatever areas of the seabed are accessible and appear to have some economic value. Permits for exploration of the ocean bottom have been granted by the United States as far as 100 miles from its coast and in water depths up to 6,000 feet; Australia has issued an exploration permit for an area 200 miles from its coast and both Honduras and Nicaragua have licensed exploration out to 225 miles. By legislation or constitutional provision several States claim a "continental shelf defined in terms of exploitability alone, a definition which is meaningless under contemporary conditions. The seabed of "closed" or relatively shallow seas is already being divided up by mutual agreement among the coastal States. Thus the bed of the North Sea was parceled out among the littoral States in 1964 and this year Italy and Jugoslavia divided between themselves most of the floor of the Adriatic.

Although the greater part of the North Sea and Adriatic comes within a reasonable geophysical definition of the continental shelf, these unchallenged arrangements may foreshadow a division of all the closed seas of the world. Moreover, claims to jurisdiction over the ocean floor and its subsoil based on the test of exploitability alone, or action implying claims to jurisdiction at great distances from the coast, may signal the initial stages either of a distribution of the entire ocean floor of the world among the coastal States or of a race to grab and hold lands anywhere under the high seas. This year a company with British and American capital claimed, by a notice in the London Daily Express, an area of 270 square miles in the Red Sea for the purpose of exploiting one of its in-solution concentrations of minerals.

The intolerable injustice of reserving the plurality of the world's resources for the exclusive benefit of a handful of nations has been recognized by President Johnson. More than two years ago he said: "Under no circumstances, we believe, must we ever allow the prospects of rich harvest and mineral wealth to create a new form of colonial competition among the maritime nations. We must be careful to avoid a race to grab and hold the lands under the high seas. We must ensure that the deep seas and the ocean bottoms are, and remain, the legacy of all human beings."

IV

What are the alternatives to a policy of wait-and-see? One has already been mentioned. The international community might agree that only coastal States have the right to exploit the ocean floor and that the floor itself be divided among them in accordance with the principles of the 1958 Geneva Convention.

This solution could be very attractive for some countries and presents certain advantages. It would end controversy about the limits of the continental shelf and permit each State to protect claims of exclusive rights within its area. Mining companies would deal with national governments as they have in the past. Coastal States would be insured against foreign installations near their shores. Possible international disputes over conflicting claims would be minimized, and so on. Provision could even be made to institute some sort of tax or royalty on minerals extracted by coastal States to compensate landlocked countries, or as a contribution toward some international fund to assist developing countries.

Nevertheless, a "national lake" solution has overwhelming drawbacks. It is fundamentally inequitable: some countries through accidents of geography or history would make disproportionate gains. It does not correspond to the military requirements of the major powers, hence it would not be acceptable to them, and without the consent of the major powers no agreement would be viable. It would tend to impede scientific research. Finally, it would make it difficult for the international community to adopt comprehensive and effective measures to combat the growing pollution of the seas and would be likely to impinge upon fishing and possible new uses of the seabed for transportation.

The second alternative is an international régime. This can be conceived in different ways, but it must meet certain basic criteria. In the first place it must be viable-that is, it must be acceptable to the overwhelming majority of States; and, in order to be acceptable, it must be equitable and safeguard as much as possible the legitimate interests of all. Second, an international solution must permit and if possible encourage an orderly, peaceful and economically efficient exploitation of the minerals of the ocean floor, taking into account the need to avoid serious damage to the marine environment or destructive competition with present sources of minerals. Third, it should be flexible in order to accommodate new developments involving competing uses of the sea and of the seabed. Fourth, scientific investigation and exploration should not be inhibited. Finally, and most importantly, an international régime must not jeopardize vital security interests but should provide a legal framework for the eventual demilitarization of the ocean floor.

At the General Assembly last year, Malta suggested the adoption of a resolution embodying the following concepts:

1. The sea-bed and the ocean floor are a common heritage of mankind and should be used and exploited for peaceful purposes and for the exclusive benefit of mankind as a whole. The needs of poor countries, representing that part of mankind which is most in need of assistance, should receive preferential consideration in the event of financial benefits being derived from the exploitation of the sea-bed and ocean floor for commercial purposes.

2. Claims to sovereignty over the sea-bed and ocean floor beyond present national jurisdiction, as presently claimed, should be frozen until a clear definition of the continental shelf is formulated.

3. A widely representative, but not too numerous, body should be established; in the first place to consider the security, economic and other implications of the establishment of an international regime over the deep seas and ocean floor beyond the limits of present national jurisdiction; in the second place, to draft a comprehensive treaty to safeguard the international character of the sea-bed and ocean floor beyond present national jurisdiction; and in the third place to provide for the establishment of an international agency which will ensure that national activities undertaken in the deep seas and on the ocean floor will conform to the principles and provisions incorporated in the proposed treaty.

Support for this resolution came from many countries, though several of the technologically advanced States felt they needed time to study all the facts and their implications before taking a definite position. At the suggestion of Malta, an informal group was appointed to elaborate proposals that might be acceptable to the great majority of member States. On the recommendation of this group, an essentially preparatory resolution was unanimously adopted by the General Assembly establishing an Ad Hoc Committee of 35 members to prepare a study for the consideration of the Assembly this year. This study is to include (a) a survey of past and present activities of all organizations within the United Nations family having to do with the seabed and ocean floor and of existing international agreements concerning these areas; (b) an account of the scientific, technical, economic, legal and other aspects of the item; (c) "an indication regarding practical means to promote international co-operation in the exploration, conservation and use of the sea-bed and the ocean floor and the sub-soil thereof . . . and of their resources . . . taking into account the views expressed and the suggestions put forward by Member States...."

The Ad Hoc Committee, which has held three meetings-the most recent in Rio de Janeiro in August, established two working groups, one to deal with legal matters and the other with economic and technical matters. Their discussions have served the useful purpose of clearing the ground and establishing agreed facts as a basis for future consideration of the question.

Without going into detail, it can be said that there is broad agreement on the general proposition that an undefined area of the seabed is beyond national jurisdiction and that international coöperation is desirable in the development of marine resources. But approaches to the question are widely divergent. The great oceanic maritime powers appear to favor a relatively restricted continental shelf under national jurisdiction and unrestricted access to and use of the ocean floor beyond. They are either silent or vague on the question of making provision for all countries to participate in the financial benefits that could result from the economic exploitation of the seabed. A few less technologically advanced oceanic countries, while supporting the principle that all States should participate in these potential benefits, would like to define the continental shelf as being so wide that it would extend virtually to mid- ocean; for the present these States are not anxious to proceed to consideration of a precise definition. The great majority of developing countries on the other hand, while taking various positions on the definition of the continental shelf under national jurisdiction, support the idea that this complex question urgently needs to be examined; they also strongly support the early adoption by the General Assembly of general principles with regard to the exploration and use of the seabed.

It is encouraging that all States have supported the notion that the ocean floor should be used for peaceful purposes, but there is a deep divergence between those which favor complete demilitarization and those which would be satisfied with more limited arms-control measures. Finally, although there is virtual unanimity with regard to the need to ensure freedom of scientific research and for international coöperation to control pollution of the seas, there do not appear to be clear ideas as to what specific action should be taken. In view of the divergence in outlook and approach among the countries represented on the Ad Hoc Committee, it is unlikely that the report which will be submitted to the General Assembly this fall will contain more than a limited number of general conclusions and recommendations.

I hope, however, that it will be possible to muster agreement this autumn to establish a committee to provide continuing coördination of international and inter-governmental activities involving the seabed and to examine the merits of the various plans that can be envisaged for control of the ocean floor. I also hope that it will be possible for the General Assembly at its present session to adopt a declaration firmly committing the international community to certain basic principles of action in the exploration and use of the seabed beyond national jurisdiction. Perhaps, too, the Eighteen Nation Disarmament Committee could be invited to take up the question of defining the factors vital to a workable, verifiable and effective agreement for the demilitarization of the ocean floor so that this crucial but complex matter can be constructively considered next year.

These would represent useful first steps toward serious consideration of an international régime for the seabed and of the international machinery that would be required to administer it for the benefit and in the interests of all. 1 The land underlying the seas and oceans may be broadly divided into the continental shelf, the continental slope and the abyss. The geophysical continental shelf is commonly defined as that area of the sea or ocean floor between the mean low-water line and that sharp change in the inclination of the floor that marks the inner edge of the continental slope. The sharp change in inclination occurs at varying depths from 150 to 1,500 feet, but usually around the 400 to 500 foot isobath. The width of the shelf ranges from less than one mile to approximately 800 miles. Continental shelves can be generally characterized as the submerged extensions of adjacent land areas. The geophysical definition of the continental shelf must be distinguished from the legal definition which was adopted by the 1958 United Nations Conference on the Law of the Sea. The continental slope, usually from ten to twenty miles wide, extends from the outer edge of the continental shelf to the abyss or the ocean floor. The abyss or ocean floor appears to be a rolling plain from 10,000 to 15,000 feet below the surface of the sea; it is scarred by deep gorges called trenches and studded with sea mounts and guyots. The mean depth of the world's oceans is about 11,500 feet; more than 75 percent of the ocean floor lies at a depth of less than 15,000 feet. Great submarine mountain ranges rise from the ocean floor and often demarcate ocean basins. The mid- Atlantic ridge, frequently rising 10,500 feet above the ocean floor, extends the entire length of the Atlantic. The mid-Oceanic ridge, extensively mapped during the years 1959-65 by the International Indian Ocean Expedition, curves in a great arc, in places 1,500 miles broad, from the Arabian peninsula to the Crozet Islands, rising occasionally 15,000 feet above the abyss. 2 All parts of the ocean floor have, of course, been accessible by bathyscaph, since the deepest part of the ocean, the bottom of the Mariana trench, was reached by Auguste Piccard eight years ago. Bathyscaphs, however, are unwieldy vehicles which have serious limitations. 3 As quoted in U.S. News and World Report, August 5, 1968. Most of "the outer continental shelf" lies beyond the geophysical shelf.

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