opinion: MR. Justice Harlan
  delivered the opinion of the Court.
  The present case requires us to determine the extent of submerged lands granted to the State of California by the Submerged Lands Act of 1953, and in particular to declare whether specified bodies of water on the California coast are “inland waters” within the meaning of that Act. A substantial amount of background is necessary to place the issues in perspective.
  I.
  The Setting op the Case.
  This is a suit begun in 1945, brought by the United States against California to determine dominion over the submerged lands and mineral rights under the three-mile belt of sea off the coast of California. In 1947 the Court decreed:
  “The United States of America is now, and has been at all times pertinent hereto, possessed of paramount rights in, and full dominion and power over, the lands, minerals and other things underlying the Pacific Ocean lying seaward of the ordinary low-water mark on the coast of California, and outside of the inland waters, extending seaward three nautical miles .... The State of California has no title thereto or property interest therein.” United States v. California, 332 U. S. 804, 805, Order and Decree.
  After the entry of this decree, the United States asked that the lands awarded to it be defined in greater detail in certain areas where there was substantial oil well activity, and which California asserted lay within inland waters. The Court appointed a Special Master, and directed him to consider seven specified segments of the California coast to determine the line of ordinary low water and the outer limit of inland waters. These segments included various bays, and, as the problem evolved, the so-called “overall unit area” consisting of the waters inside a line encompassing the islands off the shore of southern California, some as far as 50 miles out. The Special Master’s Report, generally favoring the position of the United States, was filed with this Court in November 1952, 344 U. S. 872. He adopted as his criteria for defining inland waters those applied by the United States in the conduct of its foreign affairs as of the date of the California decree, October 27, 1947 — in particular, a rule that only a bay having a closing line across its mouth no more than 10 miles in length and enclosing a sufficient water area to satisfy the so-called Boggs formula would be inland water, with the qualification that a bay which had been historically considered inland water would so continue. Both parties noted their exceptions to the Report, but before any further action was taken, Congress enacted the Submerged Lands Act.
  The Submerged Lands Act grants to the States “title to and ownership of the lands beneath navigable waters within the boundaries of the respective States.” § 3 (a). “Boundaries” includes the seaward boundaries of a State “as they existed at the time such State became a member of the Union, or as heretofore approved by the Congress,” but subject to the limitation that
  “in no event shall the term ‘boundaries’ ... be interpreted as extending from the coast line more than three geographical miles into the Atlantic Ocean or the Pacific Ocean, or more than three marine leagues into the Gulf of Mexico.” § 2 (b).
  “Coast line” is then defined as the composite “line of ordinary low water along that portion of the coast which is in direct contact with the open sea and the line marking the seaward limit of inland waters.” § 2 (c). For States having no previously approved seaward boundaries the Act provides that “[a]ny State admitted subsequent to the formation of the Union which has not already done so may extend its seaward boundaries to a line three geographical miles distant from its coast line . . . .” § 4.
  Thus the Act effectively grants each State on the Pacific coast all submerged lands shoreward of a line three geographical miles from its “coast line,” derivatively defined in terms of “the seaward limit of inland waters.” “Inland waters” is not defined by the Act.
  In a later measure related to the Submerged Lands Act, Congress declared that the United States owned all submerged land in the continental shelf seaward of the lands granted to the States. Outer Continental Shelf Lands Act, 67 Stat. 462, 43 U. S. C. § 1331 et seq.
  The passage of the Submerged Lands Act marked the beginning of a long halt in the proceedings in this case. Depth of California’s coastal waters increases very rapidly, and as of May 22, 1953, the date of enactment, it was impractical to drill for oil except close to the shore. By granting to California the mineral rights in the three-mile belt, the Act vested in California all the interests that were then thought to be important, and no further action was taken on the Special Master’s Report. That Report was neither adopted, modified, nor rejected by this Court, but was simply allowed to lie dormant. By 1963, however, drilling techniques had improved sufficiently to revitalize the importance of the demarcation line between state and federal submerged lands. The United States filed an amended complaint reviving the Special Master’s Report and redescribing the issues as modified by the Submerged Lands Act; both the United States and California filed new exceptions to the Report, and the case is now ready for decision.
  The basic contention of the United States is that the Act simply moved the line of demarcation out three miles from the line established by the California decree. Therefore, contends the United States, the Special Master’s Report on the line of ordinary low water and the outer limit of inland waters as used in the California decree is just as relevant now as it was before Congress acted, and, with slight modifications, the line drawn by the Special Master should be taken as the “coast line” for purposes of the Submerged Lands Act. California asserts that whereas the Special Master determined inland waters to be those which the United States would have claimed as such for purposes of international relations, the Submerged Lands Act used the term in an entirely different sense to mean those waters which the States historically considered to be inland — in California’s case, those waters which the State considered to be inland at the time it entered the Union. Therefore, according to California, the line drawn in the Special Master’s Report was determined under standards wholly foreign to the Submerged Lands Act.
  The focal point of this case is the interpretation to be placed on “inland waters” as used in the Act. Since the Act does not define the term, we look to the legislative history.
  II.
  Legislative History Reveals that Congress Meant to Leave the Definition of Inland Waters to the Courts.
  Two changes relevant for our purposes were made in the bill which became the Submerged Lands Act between the time it was sent to the Senate Committee on Interior and Insular Affairs and the time of its passage.
  (1) As first written, the bill defined inland waters to include
  “all estuaries, ports, harbors, bays, channels, straits, historic bays, and sounds, and all other bodies of water which join the open sea.”
  This definition was removed by the Senate Committee.
  (2) The bill originally contained no limitation on the extent of historic boundaries that could be claimed. The provision limiting the extent of boundary claims to no more than three geographical miles from the coastline on the Atlantic and Pacific Oceans and three marine leagues on the Gulf of Mexico was added to the bill on the floor of the Senate in the late stages of the debates.
  Removal of the definition for inland waters and the addition of the three-mile limitation in the Pacific, when taken together, unmistakably show that California cannot prevail in its contention that “as used in the Act, Congress intended inland waters to identify those areas which the states always thought were inland waters.” By deleting the original definition of “inland waters” Congress made plain its intent to leave the meaning of the term to be elaborated by the courts, independently of the Submerged Lands Act.
  In response to substantial objections made in the hearings to the original bill’s broad definition of inland waters on grounds that it would prejudice and limit the position which the United States could take in its future conduct of foreign affairs, Senator Cordon, the manager of the bill, recommended and obtained elimination of the definition. The Committee Report which he authored explained:
  “The words 'which include all estuaries, ports, harbors, bays, channels, straits, historic bays, and sounds, and all other bodies of water which join the open sea’ have been deleted from the reported bill because of the committee’s belief that the question of what constitutes inland waters should be left where Congress finds it. The committee is convinced that the definition neither adds nor takes away anything a State may have now in the way of a coast and the lands underneath waters behind it.” S. Rep. No. 133, 83d Cong., 1st Sess., 18.
  The committee’s understanding that the measure “neither adds nor takes away anything a State may have now in the way of a coast and the lands underneath waters behind it,” appears to be an acceptance of “inland waters” as used in the California and prior Court opinions, whatever that usage might have been. Various different concepts of inland waters were asserted during the Senate Hearings, based on such elements as the depth of the water, the width of the opening of a coastal indentation, the Boggs formula, and the common designation of bodies of water as bays, sounds, straits, etc. When it became clear that the question had highly technical aspects (see, e. g., n. 5, supra) and was one on which differences would arise, the Senate Committee adopted the expedient solution of leaving the matter just as it had found it, neither accepting nor rejecting any particular rule or formula. It intended to leave unaffected the judicial view of inland waters and the judicial responsibility for particularizing it.
  Reference to Senator Cordon’s request to the Senate Committee for deletion of the objectionable clause confirms that understanding. He said:
  “The matter of inland waters is one that has been defined time and time again by the courts, not, I believe, in any one all-inclusive definition, but it was felt [by those who objected to the definition during the hearings] that the use of these words were [sic] an attempted legislative definition of the term 'inland waters,’ and it was inadvisable for us in this bill, which is a transfer of title, to attempt to make law in the other field of what is or is not inland water.
  “The use of the language, it was felt, would probably raise questions that have not been raised, whereas the present definitions are in- the decisions and available to the court.”
  “Senator MALONE. The inland waters had a special master for that particular job, did they not, and that is now under consideration, that is, his report is under consideration by the Supreme Court?
  “Senator CORDON. With respect to California, and a portion of California coast; yes.” Senate Hearings 1304-1305.
  Shortly thereafter there follows a virtually conclusive statement:
  “Senator CORDON. It was not the chairman’s view that we were attempting to draw a line delimiting inland waters, but that we were using a term that is well known in the law and is defined by the Court in the California case, for instance, and in the Louisiana case, I assume. That line might still be defined, even though the area may not now have the same legal status as it had before.” Id., at 1376. (Emphasis added.)
  California fastens on a statement made in the Committee Report with regard to the eliminated definition:
  “The elimination of the language, in the committee’s opinion, is consistent with the philosophy of the Holland bill to place the States in the position in which both they and the Federal Government thought they were for more than a century and a half, and not to create any situations with respect thereto.” S. Rep. No. 133, 83d Cong., 1st Sess., 18.
  From this California reasons that “inland waters” must have been intended to encompass all waters which the States “thought” were inland waters, for that is the only way in which the Act can now be interpreted to effectuate fully its supposed “philosophy” of granting to the States all submerged lands within their historic boundaries.
  If such a view of the bill’s purpose is accepted as of the time that the Committee Report was written, there is, nonetheless, no inconsistency whatsoever between that purpose and a legislative intent to leave the definition of inland waters to the courts without restriction; at that time the limitation on boundary claims had not yet been incorporated into the Act; thus as the Act was then written, States could have claimed all submerged lands within their historic boundaries, no matter how “inland waters” was defined. The definition would have affected only those States which, not having adequate pre-existing seaward boundaries, chose to extend their boundaries three miles from the coastline pursuant to § 4 of the Act. As stated by Senator Cordon during the Hearings,
  “this bill has two approaches to a determination of the area of its application. The first approach is that of the boundaries of the States when they came into the Union; second, an election to any State that has not done so to extend its boundary 3 geographical miles from its present coastline, as that term is described in the present tense in the bill.” Senate Hearings 1374.
  Only with the adoption of the three-mile limitation on the Atlantic and Pacific Oceans and the three-league limitation in the Gulf of Mexico did the interpretations of historic boundaries and inland waters become operationally related, and any inconsistency thus created between the limitation and the prior philosophy of the Act shows only that, to the extent the limitation would come into play, the philosophy was modified. This amendment was one of very few made to the bill as reported by the Senate Committee, and came as the result of continuous criticism throughout the course of the debates that the extent of the grant was indefinite, and that coastal States could engage in a “claiming race” for submerged lands. California points to language stating that adoption of the limitation worked no significant change in the bill. 99 Cong. Rec. 4114-4116 (remarks of Senator Holland). But such statements simply reflect the understanding of the major supporters of the bill that no States other than Texas and Florida (on its Gulf side) had provable claims beyond three miles, and that the claims of those two States did not go beyond three leagues. If such were the case, the limitation could indeed be thought to have no effect, for no state boundaries would run afoul of it, and the vast grant of submerged lands up to three miles along the length of the Atlantic and Pacific coasts, and three leagues, subject to historical proof, in the Gulf of Mexico, would not be impaired. Senator Holland, the author of the bill, proposed the limiting boundary amendment to meet the fears of those Senators who had criticized the indefiniteness of the bill. He explained:
  “. . . I think the amendment has very little effect. But I am perfectly willing to meet the suggestions of my friends, some of whom have been opponents, and some of whom have been supporters of the joint resolution, to the effect that they would like to have the language more clearly spelled out than it was in the original measure, to the effect that there is no intention whatsoever to grant boundaries beyond 3 geographical miles in either the Atlantic or the Pacific, and that this Congress knows of no possible situation under which greater boundaries are claimed or could be granted in the Gulf of Mexico than 3 leagues; and, in that case, this Congress knows, although this amendment does not indicate it, that there are but 2 States affected by that particular situation.” 99 Cong. Rec. 4116.
  Senator Holland was aware of California’s expansive inland water claims, but thought them altogether untenable.
  “Mr. HOLLAND. My understanding is that California has no provable case beyond 3 miles from its mainland; and that as to the islands, its provable case would be 3 miles around each of the islands. I so stated in the hearings on this matter.
  “Mr. DOUGLAS. That is a consummation devoutly to be desired, but I am not at all satisfied that that is what the Senator’s joint resolution would accomplish, because the coastline is not fully and clearly defined.
  “Mr. HOLLAND. Under the joint resolution, no such contention could be maintained.
  “Mr. DOUGLAS. Is the Senator certain of that?
  “Mr. HOLLAND. That is what I believe, and that is what every legal authority I have consulted on the subject believes. Incidentally, the only reason why there was some thought to the contrary was some wording in the original joint resolution, which has been omitted, which would have made the outer boundary of inland waters farther out than that which is now provided by the joint resolution. The joint resolution simply continues the outer boundary of inland waters pursuant to the decisions of the Supreme Court already made. . . .
  “The Senator from Florida knows full well that if the United States Supreme Court should change its mind as to what constituted the outer limits of inland waters, and should change it to a sufficient degree, it could open up, not only under this joint resolution, but of its own initiative, questions which would reach out much farther than anything we have been talking about here.
  “The Senator from Florida believes that the laws, as announced over and over and over again by the Supreme Court, as to the delimitation of inland waters, are sufficiently fixed, definite, and certain so that it would require a complete, cataclysmic change of the Supreme Court’s philosophy in that field to afford any hope for an extension of the boundaries of the good State of California so that they would go out beyond the islands as to all areas contained within an outer line. There is no way for us to foreclose the Supreme Court from changing its mind. It might change its mind with reference to inland waters and their delimitation. But failing, such change, the Senator from Florida cannot see how, under this joint resolution, there could possibly be any serious question affecting California or any other State.” 99 Cong. Rec. 2756-2757.
  Senator Holland did not wish to foreclose California from arguing (as it has done both here and before the Special Master) that its waters are inland within the appropriate judicial definition, but it was his opinion that no such definition would permit California’s claim to all waters shoreward of their remote islands to prevail. Congress could have defined inland waters as it wished for the purely domestic purposes of the Submerged Lands Act. See United States v. Louisiana, 363 U. S. 1, 30-36. It could have adopted California’s theory, or the Special Master’s theory, or any other. Instead, it chose to leave the definition of inland waters where it found it — in the Court’s hands. The Act does not reveal a particular intent that courts should broadly interpret “inland waters” so as to restore California to its historic expectations regardless of what its expectations might be. Indeed, if the Court is to draw any inference from the intent and structure of the Act as to how inland waters should be defined, the most plausible inference would be that Congress, in adopting the three-mile limitation, must have intended some base line to be used other than one dependent upon each State’s subjective concept of its inland waters, for such a limitation would prove to have been none at all, as full acceptance of California’s claims in the present case would show.
  III.
  The Meaning of “Inland Waters” in the Submerged Lands Act Should Conform to the Convention on the Territorial Sea and the Contiguous Zone.
  We turn, then, to determining the judicial definition of “inland waters.” It immediately appears that the bulk of cases cited by Congressmen during debates on the Submerged Lands Act for the proposition that inland waters have “been defined time and time again by the courts” deal with interior waters such as lakes and rivers, and provide no assistance in classifying bodies of water which join the open sea. In this latter context no prior case in this Court has ever precisely defined the term. The 1947 California opinion clearly indicated that “inland waters” was to have an international content since the outer limits of inland waters would determine the Country’s international coastline, but the Court did not particularize the definition. It was that task which subsequently led to the appointment of the Special Master.
  The Special Master found that there was no internationally accepted definition for inland waters and decided, in those circumstances, that it was the position which the United States took on the question in the conduct of its foreign affairs which should be controlling. He considered the relevant date on which to determine our foreign policy position to be the date of the California decree, October 27, 1947. He therefore rejected the assertion that letters from the State Department written in 1951 and 1952 declaring the then present policy of the United States were conclusive on the question before him. At the same time that decision required the Special Master to consider a great many foreign policy materials dating back to 1793 in an attempt to discern a consistent thread of United States policy on the definition of inland waters. He ultimately decided that as of 1947 the United States had taken the position that a bay was inland water only if a closing line could be drawn across its mouth less than 10 miles long enclosing a sufficient water area to satisfy the Boggs formula.
  Since the filing of the Special Master’s Report the policy of the United States has changed significantly. Indeed it may now be said that there is a settled international rule defining inland waters. On March 24, 1961, the United States ratified the Convention on the Territorial Sea and the Contiguous Zone (T. I. A. S. No. 5639) and on September 10, 1964, when the requisite number of nations had ratified it, the Convention went into force. For nations which do not use a straight-base-line method to define inland waters (see United Kingdom v. Norway, [1951] I. C. J. Rep. 116), the Convention permits a 24-mile maximum closing line for bays and a “semicircle” test for testing the sufficiency of the water area enclosed. The semicircle test requires that a bay must comprise at least as much water area within its closing line as would be contained in a semicircle with a diameter equal to the length of the closing line. Unquestionably the 24-mile closing line together with the semicircle test now represents the position of the United States.
  The United States contends that we must ignore the Convention on the Territorial Sea and the Contiguous Zone in performing our duty of giving content to “inland waters” as used in the Submerged Lands Act, and must restrict ourselves to determining what our decision would have been had the question been presented to us for decision on May 22, 1953, the date of enactment. At that time there was no international accord on any definition of inland waters, and the best evidence (although strenuously contested by California) of the position of the United States was the letters of the State Department which the Special Master refused to treat as conclusive.
  We do not think that the Submerged Lands Act has so restricted us. Congress, in passing the Act, left the responsibility for defining inland waters to this Court. We think that it did not tie our hands at the same time. Had Congress wished us simply to rubber-stamp the statements of the State Department as to its policy in 1953, it could readily have done so itself. It is our opinion that we best fill our responsibility of giving content to the words which Congress employed by adopting the best and most workable definitions available. The Convention on the Territorial Sea and the Contiguous Zone, approved by the Senate and ratified by the President, provides such definitions. We adopt them for purposes of the Submerged Lands Act. This establishes a single coastline for both the administration of the Submerged Lands Act and the conduct of our future international relations (barring an unexpected change in the rules established by the Convention). Furthermore the comprehensiveness of the Convention provides answers to many of the lesser problems related to coastlines which, absent the Convention, would be most troublesome.
  California argues, alternatively to its claim that “inland waters” embraces all ocean areas lying within a State’s historic seaward boundaries, that if Congress intended “inland waters” to be judicially defined in accordance with international usage, such definition should possess an ambulatory quality so as to encompass future changes in international law or practice. Thus, if 10 years from now the definitions of the Convention were amended, California would say that the extent of the Submerged Lands Act grant would automatically shift, at least if the effect of such amendment were to enlarge the extent of submerged lands available to the States. We reject this open-ended view of the Act for several reasons. Before today’s decision no one could say with assurance where lay the line of inland waters as contemplated by the Act; hence there could have been no tenable reliance on any particular line. After today that situation will have changed. Expectations will be established and reliance placed on the line we define. Allowing future shifts of international understanding respecting inland waters to alter the extent of the Submerged Lands Act grant would substantially undercut the definiteness of expectation which should attend it. Moreover, such a view might unduly inhibit the United States in the conduct of its foreign relations by making its ownership of submerged lands vis-á-vis the States continually dependent upon the position it takes with foreign nations. “Freezing” the meaning of “inland waters” in terms of the Convention definition largely avoids this, and also serves to fulfill the requirements of definiteness and stability which should attend any congressional grant of property rights belonging to the United States.
  IV.
  Subsidiary Issues.
  Once it is decided that the definitions of the Convention on the Territorial Sea and the Contiguous Zone apply, many of the subsidiary issues before us fall into place.
  1. Straight Base Lines. — California argues that because the Convention permits a nation to use the straight-baseline method for determining its seaward boundaries if its “coast line is deeply indented and cut into, or if there is a fringe of islands along the coast in its immediate vicinity,” California is therefore free to use such boundary lines across the openings of its bays and around its islands. We agree with the United States that the Convention recognizes the validity of straight base lines used by other countries, Norway for instance, and would permit the United States to use such base lines if it chose, but that California may not use such base lines to extend our international boundaries beyond their traditional international limits against the expressed opposition of the United States. The national responsibility for conducting our international relations obviously must be accommodated with the legitimate interests of the States in the territory over which they are sovereign. Thus a contraction of a State’s recognized territory imposed by the Federal Government in the name of foreign policy would be highly questionable. But an extension of state sovereignty to an international area by claiming it as inland water would necessarily also extend national sovereignty, and unless the Federal Government’s responsibility for questions of external sovereignty is hollow, it must have the power to prevent States from so enlarging themselves. We conclude that the choice under the Convention to use the straight-base-line method for determining inland waters claimed against other nations is one that rests with the Federal Government, and not with the individual States.
  California relies upon Manchester v. Massachusetts, 139 U. S. 240, for the proposition that a State may draw its boundaries as it pleases within limits recognized by the law of nations regardless of the position taken by the United States. Although some dicta in the case may be read to support that view, we do not so interpret the opinion. The case involved neither an expansion of our traditional international boundary nor opposition by the United States to the position taken by the State.
  2. Twenty-jour-mile Closing Rule. — The Convention recognizes, and it is the present United States position, that a 24-mile closing rule together with the semicircle test should be used for classifying bays in the United States. Applying these tests to the segments of California’s coast here in dispute, it appears that Monterey Bay is inland water and that none of the other coastal segments in dispute fulfill these aspects of the Convention test. We so hold.
  California asserts that the Santa Barbara Channel may be considered a “fictitious bay” because the openings at both ends of the channel and between the islands are each less than 24 miles. The United States argues that the channel is no bay at all; that it is a strait which serves as a useful route of communication between two areas of open sea and as such may not be classified as inland waters.
  By way of analogy California directs our attention to the Breton and Chandeleur Sounds off Louisiana which the United States claims as inland waters, United States v. Louisiana, 363 U. S. 1, 66-67, n. 108. Each of these analogies only serves to point up the validity of the United States’ argument that the Santa Barbara Channel should not be treated as a bay. The Breton Sound is a cul de sac. The Chandeleur Sound, if considered separately from the Breton Sound which it joins, leads only to the Breton Sound. Neither is used as a route of passage between two areas of open sea. In fact both are so shallow as to not be readily navigable. California also points to the Strait of Juan de Fuca. That strait is not claimed by the United States as a “fictitious bay” and it does not connect two areas of open sea.
  Evidence submitted to the Special Master on the extent of international use made of the Santa Barbara Channel was sparse. What evidence there was indicated the usefulness of the route, but did not specify whether the ships so using it were domestic or international. California now regards the point as important, for under international law as expressed in the Corfu Channel Case, [1949] I. C. J. Rep. 4, the International Court of Justice held that a country could not claim a strait as inland water if, in its natural'state, it served as a useful route for international passage. We do not consider the point of controlling importance. The United States has not in the past claimed the Santa Barbara Channel as inland water and opposes any such claim now. The channel has not been regarded as a bay either historically or geographically. In these circumstances, as with the drawing of straight base lines, we hold that if the United States does not choose to employ the concept of a “fictitious bay” in order to extend our international boundaries around the islands framing Santa Barbara Channel, it cannot be forced to do so by California. It is, therefore, unnecessary to reinstitute proceedings before a master to determine the factual question of whether the passageway is internationally useful.
  3. Historic Inland Waters. — By the terms of the Convention the 24-mile closing rule does not apply to so-called “historic” bays. Essentially these are bays over which a coastal nation has traditionally asserted and maintained dominion with the acquiescence of foreign nations. California claims that virtually all the waters here in dispute are historic inland waters as the term is internationally understood. It relies primarily on an interpretation of its State Constitution to the effect that the state boundaries run three miles outside the islands and bays, plus several court decisions which so interpret it as applied to Monterey, Santa Monica, and San Pedro Bays The United States counters that, as with straight base lines, California can maintain no claim to historic inland waters unless the claim is endorsed by the United States. The Special Master found it unnecessary to decide that question because, on the evidence before him, he concluded that California had not traditionally exercised dominion over any of the claimed waters.
  Since the 24-mile rule includes Monterey Bay, we do not consider it here. As to Santa Monica Bay, San Pedro Bay, and the other water areas in dispute, we agree with the Special Master that they are not historic inland waters of the United States.
  California contends that two studies of the criteria for determining historic waters have been made since the Special Master filed his report which show that he applied the wrong standards, thus vitiating his conclusions. In particular it is said that the Special Master erroneously thought the concept of historic waters to be an exception to the general rule of inland waters requiring a rigorous standard of proof. We find no substantial indication of this in his report.
  On the evidence, California’s claim that its constitution set a boundary beyond the bays and islands is arguable, but many of the state statutes drawing county boundaries which supposedly run to the limit of the state boundaries cut the other way by indicating a line only three miles from shore. Furthermore, a legislative declaration of jurisdiction without evidence of further active and continuous assertion of dominion over the waters is not sufficient to establish the claim. There is a federal district court opinion, United States v. Carrillo, 13 F. Supp. 121 (1935), which dismissed federal criminal charges for an offense which took place more than three miles from the shore of San Pedro Bay on the ground that the bay was within California, not federal, jurisdiction; but it is difficult to see this dismissal as an assertion of dominion. In Santa Monica Bay, California did successfully prosecute a criminal offense which took place more than three miles from the shore, People v. Stralla, 14 Cal. 2d 617, 96 P. 2d 941 (1939). However, the decision stands as the only assertion of criminal jurisdiction of which we have been made aware.
  The United States disclaims that any of the disputed areas are historic inland waters. We are reluctant to hold that such a disclaimer would be decisive in all circumstances, for a case might arise in which the historic evidence was clear beyond doubt. But in the case before us, with its questionable evidence of continuous and exclusive assertions of dominion over the disputed waters, we think the disclaimer decisive.
  4. Harbors and Roadsteads. — The parties disagree as to whether inland waters should encompass anchorages beyond the outer harborworks of harbors. The Convention on the Territorial Sea and the Contiguous Zone (Art. 8) states without qualification that “the outermost permanent harbour works which form an integral part of the harbour system shall be regarded as forming part of the coast.” We take that to be the line incorporated in the Submerged Lands Act.
  As to open roadsteads used for loading, unloading and anchoring ships, the Convention (Art. 9) provides that such areas should be included in the territorial sea, and, by implication, that they are not to be considered inland waters. We adopt that interpretation.
  5. The Line of Ordinary Low Water. — Along the California coast there are two low tides each day, one of which is generally lower than the other. The assertion of the United States, with which the Special Master agreed, is that the line of ordinary low water is obtained by taking the average of all the low tides. California would average only the lower low tides.
  We hold that California’s position represents the better view of the matter. The Submerged Lands Act defines coastline in terms of the “line of ordinary low water.” The Convention (Art. 3) uses “the low-water line along the coast as marked on large-scale charts officially recognized by the coastal State” (i. e., the United States). We interpret the two lines thus indicated to conform, and on the official United States coastal charts of the Pacific Coast prepared by the United States Coast and Geodetic Survey, it is the lower low water line which is marked.
  6. Artificial Accretions. — When this case was before the Special Master, the United States contended that it owned all mineral rights to lands outside inland waters which were submerged at the date California entered the Union, even though since enclosed or reclaimed by means of artificial structures. The Special Master ruled that lands so enclosed or filled belonged to California because such artificial changes were clearly recognized by international law to change the coastline. Furthermore, the Special Master recognized that the United States, through its control over navigable waters, had power to protect its interests from encroachment by unwarranted artificial structures, and that the effect of any future changes could thus be the subject of agreement between the parties.
  The United States now contends that whereas the Submerged Lands Act recognized and confirmed state title within all artificial as well as natural modifications to the shoreline prior to the passage of the Act, Congress meant to recognize only natural modifications after the date of the Act. The Act, however, makes no specific reference to artificial accretions, and nowhere in the legislative history did anyone focus on the question. The United States points by analogy to the rule of property law that artificial fill belongs to the owner of the submerged land onto which it is deposited. Marine R. & Coal Co. v. United States, 257 U. S. 47, 65. We think the situation different when a State extends its land domain by pushing back the sea; in that case its sovereignty should extend to the new land, as was generally thought to be the case prior to the 1947 California opinion. The considerations which led us to reject the possibility of wholesale changes in the location of the line of inland waters caused by future changes in international law, supra, pp. 166-167, do not apply with force to the relatively slight and sporadic changes which can be brought about artificially. Arguments based on the inequity to the United States of allowing California to effect changes in the boundary between federal and state submerged lands by making future artificial changes in the coastline are met, as the Special Master pointed out, by the ability of the United States to protect itself through its power over navigable waters.
  With the modifications set out in this opinion we approve the recommendations of the Special Master. The parties, or either of them, may, before September 1, 1965, submit a proposed decree to carry this opinion into effect, failing which the Court will prepare and enter an appropriate decree at the next Term of Court.
  It is so ordered.
  The Chief Justice and Mr. Justice Clark took no part in the consideration or decision of this case.
  67 Stat. 29, 43 U. S. C. §§ 1301-1315 (1958 ed.).
  The late William H. Davis of New York City.
  The segments were as follows:
  1. From Point Conception to Point Hueneme;
  2. San Pedro Bay;
  3. From the southern extremity of San Pedro Bay to the western headland at Newport Bay;
  4. Crescent City Bay;
  5. Monterey Bay;
  6. San Luis Obispo Bay;
  7. Santa Monica Bay.
  We directed the Special Master to recommend answers to the following questions:
  “Question 1. — What is the status (inland waters or open sea) of particular channels and other water areas between the mainland and offshore islands, and, if inland waters, then by what criteria are the inland water limits of any such channel or other water area to be determined ?
  “Question É. — Are particular segments in fact bays or harbors constituting inland waters and from what landmarks are the lines marking the seaward limits of bays, harbors, rivers, and other inland waters to be drawn ?
  “Question S. — By what criteria is the ordinary low water mark on the coast of California to be ascertained?” 342 TJ. S. 891.
  California’s claim to the “overall unit area” runs from Point Conception to Richardson Rock (21 miles across water), to San Miguel Island, to Santa Rosa Island, to Gull Island; thence to Begg Rock (35.8 miles), to San Nicolas Island, to San Clemente Island (43 miles); thence back to the mainland at Point Loma (56.8 miles). San Nicolas and San Clemente Islands are over 50 miles from shore. See Map attached as Appendix C to the dissenting opinion, post, at 178.
  To determine whether a coastal indentation is of sufficient depth and shape to be inland water, the Boggs formula would (1) draw the closing line across the mouth of the indentation; (2) draw a belt around the shore of the indentation (similar to a small marginal belt) having a width equal to one-fourth the length of the closing line across the entrance; (3) compare the remaining area inside the closing line with the area of a semicircle having a diameter equal to one-half of the length of the closing line, and if the enclosed area is larger than that of the semicircle, the indentation is inland water. Boggs, Delimitation of the Territorial Sea, 24 Am. J. Int’l L. 541, 548.
  The Special Master recommended as follows:
  “Question 1: The channels and other water areas between the mainland and the offshore islands within the area referred to by California as the ‘over-all unit area’ are not inland waters. They lie seaward of the baseline of the marginal belt of territorial waters, which should be measured in each instance along the shore of the adjoining mainland or island, each island having its own marginal belt.
  “Question S: No one of the seven particular coastal segments now under consideration for precise determination and adjudication is a bay constituting inland waters. The landmarks from which the lines marking the seaward limits (the straight-line segments of the baseline of the marginal belt) of bays, harbors, rivers and other inland waters are to be drawn, are as follows:
  “Bays
  “The extreme seaward limit of inland waters of a bay is a line ten nautical miles long. For indentations having pronounced headlands not more than ten nautical miles apart, and having a depth as hereinafter defined, a straight line is to be drawn across the entrance. Where the headlands are more than ten nautical miles apart, the straight line is to be drawn across the indentation at the point nearest the entrance at which the width does not exceed ten nautical miles. In either case the requisite depth is to be determined by the following criterion: The envelope of all arcs of circles having a radius equal to one-fourth the length of the straight line shall be drawn from all points around the shore of the indentation; if the area enclosed by the straight line across the entrance and the envelope of the arcs of the circles is greater than that of a semicircle with a diameter equal to one-half the length of the line across the entrance, the waters of the indentation shall be regarded as inland waters; if otherwise, the waters of the indentation shall be regarded as open sea.
  “Harbors (Ports)
  “In front of harbors the outer limit of inland waters is to embrace an anchorage reasonably related to the physical surroundings and the service requirements of the port, and, absent contrary evidence, may be assumed to be the line of the outermost permanent harbor works.
  “River Mouths
  “Where rivers empty into the sea, the seaward limit of inland waters is a line following the general direction of the coast drawn across the mouth of the river whatever its width. If the river flows into an estuary, the rules applicable to bays apply to the estuary. “Landmarks
  “Where pronounced headlands exist at tributary waterways, the appropriate landmark is the point of intersection of the plane of ordinary low water with the outermost extension of the natural headland. Where there is no pronounced headland, the landmark is the point of intersection of the ordinary low-water mark with a line bisecting the angle between the general trend line of the ordinary low-water mark along the open coast and the general trend line of the ordinary low-water mark along the shore of the tributary waterway.
  “Question 8: The ‘ordinary low-water mark on the coast of California’ is the intersection with the shoreline (as it exists at the time of survey) of the plane of the mean of all low waters, to be established, subject to the approval of the Court, by the United States Coast & Geodetic Survey from observations made over a period of 18.6 years.” Report of Special Master 2-5 (footnotes omitted).
  The Submerged Lands Act provides in relevant part:
  “AN ACT
  “To confirm and establish the titles of the States to lands beneath navigable waters within State boundaries and to the natural resources within such lands and waters, to provide for the use and control of said lands and resources, and to confirm the jurisdiction and control of the United States over the natural resources of the seabed of the Continental Shelf seaward of State boundaries.
  “Be it enacted by the Senate and House of Representatives of the United States of America in Congress assembled, That this Act may be cited as the ‘Submerged Lands Act.’
  "TITLE I
  “definition
  “Sec. 2 [43 U. S. C. § 1301]. When used in this Act—
  “(a) The term ‘lands beneath navigable waters’ means—
  “(2) all lands permanently or periodically covered by tidal waters up to but not above the line of mean high tide and seaward to a line three geographical miles distant from the coast line of each such State and to the boundary line of each such State where in any case such boundary as it existed at the time such State became a member of the Union, or as heretofore approved by Congress, extends seaward (or into the Gulf of Mexico) beyond three geographical miles, and “(3) all filled in, made, or reclaimed lands which formerly were lands beneath navigable waters, as hereinabove defined;
  “(b) The term ‘boundaries’ includes the seaward boundaries of a State or its boundaries in the Gulf of Mexico or any of the Great Lakes as they existed at the time such State became a member of the Union, or as heretofore approved by the Congress, or as extended or confirmed pursuant to section 4 hereof but in no event shall the term ‘boundaries’ or the term 'lands beneath navigable waters’ be interpreted as extending from the coast line more than three geographical miles into the Atlantic Ocean or the Pacific Ocean, or more than three marine leagues into the Gulf of Mexico;
  “(c) The. term ‘coast line’ means the line of ordinary low water along that portion of the coast which is in direct contact with the open sea and the line marking the seaward limit of inland waters;
  “TITLE II
  “lands beneath navigable waters within state boundaries
  “Sec. 3 [43 U. S. C. § 1311]. Rights of the States.—
  “(a) It is hereby determined and declared to be in the public interest that (1) title to and ownership of the lands beneath navigable waters within the boundaries of the respective States, and the natural resources within such lands and waters, and (2) the right and power to manage, administer, lease, develop, and use the said lands and natural resources all in accordance with applicable State law be, and they are hereby, subject to the provisions hereof, recognized, confirmed, established, and vested in and assigned to the respective States or the persons who were on June 5, 1950, entitled thereto under the law of the respective States in which the land is located, and the respective grantees, lessees, or successors in interest thereof;
  “(b)(1) The United States hereby releases and relinquishes unto said States and persons aforesaid, except as otherwise reserved herein, all right, title, and interest of the United States, if any it has, in and to all said lands, improvements, and natural resources;
  “Sec. 4 [43 U. S. C. § 1312]. Seaward Boundaries. — The seaward boundary of each original coastal State is hereby approved and confirmed as a line three geographical miles distant from its coast line or, in the case of the Great Lakes, to the international boundary. Any State admitted subsequent to the formation of the Union which has not already done so may extend its seaward boundaries to a line three geographical miles distant from its coast line, or to the international boundaries of the United States in the Great Lakes or any other body of water traversed by such boundaries. Any claim heretofore or hereafter asserted either by constitutional provision, statute, of otherwise, indicating the intent of a State so to extend its boundaries is hereby approved and confirmed, without prejudice to its claim, if any it has, that its boundaries extend beyond that line. Nothing in this section is to be construed as questioning or in any manner prejudicing the existence of any State’s seaward boundary beyond three geographical miles if. it was so provided by its constitution or laws prior to or at the time such State became a member of the Union, or if it has been heretofore approved by Congress.”
  One English, statute, or land mile equals approximately .87 geographical, marine, or nautical mile. The conventional “3-mile limit” under international law refers to three geographical miles, or approximately 3.45 land miles.
  S. Rep. No. 133, 83d Cong., 1st Sess., 18.
  99 Cong. Rec. 4116. Senator Anderson proposed a similar amendment while the bill was in committee. Hearings before the Senate Committee on Interior and Insular Affairs on S. J. Res. 13 and other bills, 83d Cong., 1st Sess., 1348 (hereinafter cited as Senate Hearings). After discussion the proposal was voted down, id., at 1416.
  Closing Brief of California 14.
  Senate Hearings 312-315, 1064-1065, 1085, 1304, 1378.
  See also Senate Hearings 1285 (remarks of Senator Cordon).
  Senate Hearings 275-280.
  Id., at 1052.
  Id., at 1374-1380.
  Id., at 1380-1385.
  In the later debates, Senator Cordon answered an assertion that the committee had rejected the Boggs formula by saying, “The committee, as I recall, and I think I am correct, neither accepted nor rejected the Boggs formula or any other formula.” 99 Cong. Rec. 2633. And see the material quoted in n. 23, infra.
  See Senate Hearings 1415 (remarks of Senator Cordon).
  See, e. g., 99 Cong. Rec. 2881, 2916, 3038-3040, 3549-3564, 3655-3656, 3884-3886, 4085-4086, 4094-4099, 4109.
  99 Cong. Rec. 3655 (remarks of Senator Kilgore).
  99 Cong. Rec. 2695, 3039 (remarks of Senator Daniel), 2746 (remarks of Senator Holland), 2881 (remarks of Senator Anderson), 2916 (remarks of Senators Anderson and Douglas). Senate Hearings 957 (remarks of Senator Holland).
  Several amendments were offered and defeated which would have limited the grant to the international three-mile limit or to three miles from the shoreline around the entire coastal perimeter of the United States, thus cutting off any claims to a three-league limit by the Gulf Coast States. See 99 Cong. Rec. 4157, 4203, 4473-4478. The reason for the unacceptability of these amendments to the leaders of the measure, largely composed of Senators from the Gulf Coast States, is obvious, and had nothing to do with any particular concept of inland waters.
  Senator Douglas introduced amendments specifically designed to prevent States from claiming as inland waters those water areas between the mainland and remote islands. Section 2 (c), as amended, would have read: “The term ‘coast line’ means the line of ordinary low water along that portion of the coast of the main continent which is in direct contact with the open sea and the line marking the seaward limit of inland waters, and in the case of any island seaward of such coast, means the line of ordinary low water around such island.” 99 Cong. Rec. 4240. (Amendments italicized.) The colloquy leading to the rejection of these amendments is extremely revealing in the total absence of hostility to the basic idea which Senator Douglas was pursuing and the absence of any understanding by the leaders of the measure that it embodied an historical definition of inland waters.
  “Mr. DOUGLAS. Mr. President, this amendment is designed to clear up an ambiguity in the pending joint resolution and to conform to what the distinguished Senator from Florida [Mr. Holland] the author of the joint resolution, stated was its real intention.
  “One of the problems connected with the joint resolution is the problem of where the base line is, from which the submerged lands seaward from the low-water mark are to be measured. Senate Joint Resolution 13 defines this location as the ‘coastline,’ but it is not precisely certain in my mind or in the mind of the Senator from Oregon [Mr. Cordon] whose interpretation I requested, what is meant by the word ‘coastline.’ In the main debate on the joint resolution, I pointed out that this definition might mean 1 of 2 things. First, it might mean, what I hoped it would mean; namely, the shoreline of the main continental land mass and the external limits of inland waters; and then, in the case of islands, the shorelines of each of those islands.
  “But I pointed out that probably there would be a contrary claim, particularly in the case of California, and that an attempt would be made to define the term 'coastline’ as being a line drawn from the main continent out to and along the outer edge of the outer islands lying off the coast. This is a tremendously important subject. It involves very substantial areas, particularly in the case of California. If it is the latter definition which is to be used, then the water between the remote islands — however far out — and the main continental land mass would become inland waters, not external waters, and all the intervening submerged lands would become the property of the coastal State.
  “Mr. LONG. Mr. President, I can understand the argument made by the Senator from Illinois, but I believe his amendment completely fails to reach the objective he is striving to achieve.
  “If one examines the testimony of the representative of the Department of State, he will see that it is the position of the State Department of the present administration, as it was also the position of the previous administration, and, so far as I know, of all other administrations, that the marginal sea begins Wherever the line of inland waters ends. That is a very simple position to take in the case of a straight coast line, as is the situation with regard to the State of Texas. There the shore line and the coast line are synonymous in almost all instances.
  “However, the situation becomes more complicated when we consider a coast having many indentures, islands, sounds, coves, bays, and the like. At present there is a difference of opinion between the State governments and the Federal Government as to precisely where the line of inland waters is located. But it is well agreed, as it has always been agreed, that the marginal sea begins at the point where the fine of inland waters ends.
  “I should like to apply that definition to the State of Louisiana. I regret that I do not have here a map of Louisiana for the purpose of demonstrating my point, but all who have made a study of the question agree that a body of water known as Chandeleur Sound is inland water. In that area there is a large number of islands, each island close to another. It is agreed by both the Federal Government and the State government, and it has always been agreed, that Chan-deleur Sound is inland water. The effect of the Douglas amendment would be to make Chandeleur Sound a part of the high seas, although the Federal Government has never contended that Chandeleur Sound was a part of the high seas, and the State government has always claimed it was inland water.
  “Likewise, in the case of bays, it is the position of the State Department that bays not wider than 10 miles are inland waters. The distance of 10 miles between headlands across the mouth of a bay marks the place where the marginal sea begins. The amendment offered by the Senator from Illinois would have the effect once again of declaring such a bay to be a part of the high seas, merely because it is wider than 6 miles between headlands.
  “Obviously, the Senator from Illinois is submitting his own definition of inland waters. In effect, it is a definition of inland waters which does not have the support of a single State government in the United States; it does not have the support of the State Department; it is a definition that does not meet with the approval of the Department of Justice; it is a definition, in effect, that does not meet with the approval of a single department of either the Federal Government or the State governments.
  “There is no authority for accepting the inference of this amendment, namely, that the definition of inland waters is that they begin at the shore line or where 3-mile lines from headlands intersect in a bay. There is no support for this type of amendment, other than that it appeals to the Senator from Illinois.
  “The committee has struggled with this problem. The committee struggled with several different formulas for defining inland waters. Originally, the joint resolution provided that inland waters should include all bays, sounds, straits, and estuaries. However, there was some objection to that definition by the Department of Justice. The Department of Justice contended that it would be far more preferable not to attempt to define inland waters, but simply to use the words ‘inland waters,’ to meet the standard that those words would ordinarily suggest. Therefore, at the suggestion of the Department of Justice, and I suppose with the support of the Department of State, the words ‘including all bays, estuaries, straits, and sounds/ were stricken from the joint resolution.
  “I submit that the language of the joint resolution is the best agreement that could be reached, upon the advice of the competent officials of the State Department and the Justice Department, as well as the advice that the committee had available to it from all the witnesses who testified, and therefore we should retain the committee language rather than accept the definition of the Senator from Illinois.
  “Mr. DANIEL. Is it not true that there are some islands off the main continent which are not as far as 3 miles distant, and that this amendment would confuse the situation with reference to them? . . . We would have to apply this amendment instead of the present rule of inland waters which permits both the Nation and the State to measure from the outer line along those islands.
  “Mr. HOLLAND. . . .
  "I think I understand what the Senator [Douglas] is trying to attain. What he is trying to attain is in complete accord with the belief of the Senator from Florida, that islands which are far remote from the coast, and clear beyond inland waters by any reasonable conception, have a 3-mile submerged shelf around each of them; and while that fact is clearly shown in the statement of international law furnished to the committee in the last Congress by the Secretary of State at that time, Mr. Dean Acheson, the proposed amendment would not effectuate that situation at all . . . .”
  The amendment was defeated 50 to 26. 99 Cong. Rec. 4240-4243.
  See, e. g., 99 Cong. Rec. 3110-3112 (remarks of Senator Hill).
  The 1947 case raised the purely legal question — who owned the lands and mineral rights beneath the marginal sea belt? In deciding that they belonged to the United States the Court relied heavily on the international responsibilities of the Federal Government.
  “But whatever any nation does in the open sea, which detracts from its common usefulness to nations, or which another nation may charge detracts from it, is a question for consideration among nations as such, and not their separate governmental units. What this Government does, or even what the states do, anywhere in the ocean, is a subject upon which the nation may enter into and assume treaty or similar international obligations.” 332 U. S. 19, 35 (footnote omitted).
  The opinion also established that landlocked waters not a part of the open sea are not part of the marginal belt, and belong to the States. The only problem remaining in the way of actually fixing the location of the marginal belt, and hence the dividing line of ownership between the State and the United States, was that of determining where the open sea ends and landlocked waters begin. The-Court specifically left that question unresolved. It is precisely that problem of defining what constitutes open sea and what constitutes inland waters which we must decide- in the present case.
  Resolution of that question will (1) determine for the present the location of the marginal belt which we claim against other nations, and (2) define the areas within which ships of foreign nations have no right of innocent passage. Unquestionably, the definitions of what constitutes open sea and inland waters is, to borrow the words of the 1947 opinion, “a subject upon which the nation may enter into and assume treaty or similar international obligations.” Negotiations at The Hague beginning in 1930 were directed to just that end, and the Convention on the Territorial Sea and the Contiguous Zone, to which we became a party in 1961, now establishes rules for separating the open sea from inland waters.
  Letter from Acting Secretary of State Webb to Attorney General McGrath, November 13, 1951, Senate Hearings 460; letter from Secretary of State Acheson to Attorney General McGrath, February 12, 1952, Senate Hearings 462.
  See n. 5, supra. Neither the Special Master nor the United States treated the Boggs formula as having been the “definitive” United States position. The Special Master recommended it as an “appropriate technical method” for measuring the sufficiency of the depth of bays. Report of Special Master 26.
  See n. 34, infra.
  Letter from Dean Rusk, Secretary of State, to Robert Kennedy, Attorney General, January 15, 1963, II International Legal Materials 527.
  See discussion and legislative history, Part II, supra.
  See 99 Cong. Rec. 2633 (remarks of Senators Long and Cordon).
  The Convention was approved by the Senate May 26, 1960, 106 Cong. Rec. 11196, and was ratified by the President March 24, 1961, 44 State Dept. Bull. 609. See Treaties in Force — January 1, 1965, 263.
  In support of the position that we. should ignore the developments in the law and practice of nations respecting the concept of inland waters which have transpired subsequent to the passage of the Submerged Lands Act — a position which the Solicitor General frankly recognized in his oral presentation was not an easy one for the Government to maintain — the United States cites a statement made by Senator Cordon during the hearings.
  “Those who prepared the bill over the years took the view — and that is the way the bill is before us — that 'coastline’ means the line of ordinary low water along that portion of the coast which is in direct contact with the open sea and the line marking the seaward limit of inland waters. That is in the present tense. It is the coastline as of now. We have confirmed here 3 miles from the coastline as of now. . . .
  “If we attempt now to discuss a coastline of 1783, or whenever the Revolutionary War was concluded and the treaty was signed— and I do not just now recall the date — if we attempt now to determine a coastline as of then, it would seem to me that we increase our difficulties beyond what, as I understand the bill, we envisioned in the first place, but which we left where they were.” Senate Hearings 1354-1355.
  That statement was made in reply to a suggestion that a State should have the choice of extending its boundaries three miles from its present coastline or three miles from its coastline as of the time it entered the Union. Senator Cordon’s reply expresses his opposition to that idea on the ground that the exact location of the ancient shoreline would be extremely difficult to determine. It reveals no intent to restrict the courts in framing the definitions to be used to determine the present coastline.
  Article 4 of the Convention provides:
  “1. In localities where the coast line is deeply indented and cut into, or if there is a fringe of islands along the coast in its immediate vicinity, the method of straight baselines joining appropriate points may be employed in drawing the baseline from which the breadth of the territorial sea is measured.
  “2. The drawing of such baselines must not depart to any appreciable extent from the general direction of the coast, and the sea areas lying within the lines must be sufficiently closely linked to the land domain to be subject to the regime of internal waters.
  “3. Baselines shall not be drawn to and from low-tide elevations, unless lighthouses or similar installations which are permanently above sea level have been built on them.
  “4. Where the method of straight baselines is applicable under the provisions of paragraph 1, account may be taken, in determining particular baselines, of economic interests peculiar to the region concerned, the reality and the importance of which are clearly evidenced by a long usage.
  “5. The system of straight baselines may not be applied by a State in such a manner as to cut off from the high seas the territorial sea of another State.
  “6. The coastal State must clearly indicate straight baselines on charts, to which due publicity must be given.”
  Letter from Dean Rusk, Secretary of State, to Robert Kennedy, Attorney General, January 15, 1963, II International Legal Materials 527; Brief for the United States in Answer to California’s Exceptions 148.
  The full text of Article 7 is as follows:
  “1. This article relates only to bays the coasts of which belong to a single State.
  “2. For the purposes of these articles, a bay is a well-marked indentation whose penetration is in such proportion to the width of its mouth as to contain landlocked waters and constitute more than a mere curvature of the coast. An indentation shall not, however, be regarded as a bay unless its area is as large as, or larger than, that of the semi-circle whose diameter is a line drawn across the mouth of that indentation.
  “3. For the purpose of measurement, the area of an indentation is that lying between the low-water mark around the shore of the indentation and a line joining the low-water marks of its natural entrance points. Where, because of the presence of islands, an indentation has more than one mouth, the semi-circle shall be drawn on a line as long as the sum total of the lengths of the lines across the different mouths. Islands within a,n indentation shall be included as if they were part of the water areas of the indentation.
  “4. If the distance between the low-water marks of the natural entrance points of a bay does not exceed twenty-four miles, a closing line may be drawn between these two low-water marks, and the waters enclosed thereby shall be considered as internal waters.
  “5. Where the distance between the low-water marks of the natural entrance points of a bay exceeds twenty-four miles, a straight baseline of twenty-four miles shall be drawn within the bay in such a manner as to enclose the maximum area of water that is possible with a line of that length.
  “6. The foregoing provisions shall not apply to so-called ‘historic’ bays, or in any case where the straight baseline system provided for in article 4 is applied.”
  The parties stated that Crescent City Bay is no longer an area in dispute.
  The United States asserts that “international law recognizes no principle of ‘fictitious bays.’ ” We find it unnecessary to decide that question. The Government states:
  “The expression seems to have originated in a proposal by the Committee of Experts, made to the Fifth Session of the International Law Commission, suggesting a 10-mile rule for bays, a general 10-mile limit for straight baselines, providing that baselines should not be drawn to islands more than 5 miles from shore, and limiting baselines to 5 miles in groups of islands or between such groups and the mainland, except that in such a group one opening could be 10 miles. The latter situation'was called a‘fictitious bay.’ The Special Rapporteur adopted this proposal in an Addendum to the Second Report on the Regime of the Territorial Sea, International Law Commission, Fifth Session, 18 May 1953. English text, U. N. Doc. A/CN.4/61/Add.l, p. 7 and Annex, p. 4. The subject of groups of islands was postponed by the Commission in 1954 (Article 11, Report of the International Law Commission Covering the Work of Its Sixth Session (U. N. Doc. A/CN.4/88), p. 42), and there is no special provision on the subject in the Convention on the Territorial Sea and the Contiguous Zone as finally adopted. The Report of the International Law Commission on the Work of Its Eighth Session, p. 45, fn. 1 (U. N. Doc. A/C.6/L.378), makes clear that the original proposal on the subject was an attempt to formulate a rule and not an expression of a rule already in existence.” Brief for the United States in Answer to California’s Exceptions 149-150, n. 112.
  The openings at the ends of the Santa Barbara Channel are 11 miles and 21 miles.
  See Letter from Acting Secretary of State Webb to Attorney General McGrath, November 13, 1951. Senate Hearings 460. See also Senate Hearings 1084-1085 (remarks of Jack B. Tate).
  The depth in general ranges between 6 and 12 feet according to Coast and Geodetic Survey Chart No. 1270, but there is no passage as much as 12 feet deep connecting the ends of the sounds. The sounds are “navigable waters” in the legal sense even in the parts too shallow for navigation. See United States v. Turner, 175 F. 2d 644, 647, cert. denied, 338 U. S. 851.
  Testimony before the Special Master indicated that the channel provided a substantial amount of protection from the rough seas of the Pacific and was used as an alternate route of passage for ships “coming down from the Pacific Northwest.” (Tr. 595. See also Tr. 608.) In its appendix, p. 57, California points to a statement in Davidson, Coast Pilot of California, Oregon, and Washington (4th ed. 1889), p. 53, “The islands break the force of the large westerly swell of the Pacific along the coast-line, and in winter afford good lee from the full force of the southeast gales.”
  See Art. 7, § 6, supra, n. 36.
  See generally, Juridical Regime of Historic Waters, Including Historic Bays, U. N. Doc. A/CN.4/143 (1962).
  Article XII of the California Constitution of 1849 described the sea boundary of the State of California as follows:
  “. . . thence running west and along said boundary line to the Pacific Ocean, and extending therein three English miles; thence running in a northwesterly direction and following the direction of the Pacific Coast to the 42d degree of north latitude, thence on the line of said 42d degree of north latitude to the place of beginning. Also all the islands, harbors, and bays, along and adjacent to the Pacific Coast.”
  Ocean Industries, Inc. v. Superior Court, 200 Cal. 235, 252 P. 722 (1927); Ocean Industries, Inc. v. Greene, 15 F. 2d 862 (D. C. N. D. Cal. 1926) (Monterey Bay). People v. Stralla, 14 Cal. 2d 617, 96 P. 2d 941 (1939) (Santa Monica Bay). United States v. Carrillo, 13 F. Supp. 121 (1935) (San Pedro Bay).
  Historic Bays, U. N. Doc. A/CN.13/1 (1957), and Juridical Regime of Historic Waters, Including Historic Bays, U. N. Doc. A/CN.4/143 (1962).
  E. g., for San Diego County, see Cal. Stat. 1850, c. 15, § 2, p. 58; Cal. Stat. 1851, c. 14, §2, p. 172; Cal. Political Code 1872, §§3907, 3944; Cal. Political Code 1923, § 3945; Cal. Stat. 1919, c. 470, § 38, p. 895; Cal. Stat. 1923, c. 160, §38, p. 361; Cal. Govt. Code §23137; Cal. Stat. 1947, c. 424, p. 1069. Por Los Angeles County, see Cal. Stat. 1850, c. 15, §3, p. 59; Cal. Stat. 1851, c. 14, §3, p. 172; Cal. Stat. 1856, c. 46, § 1, p. 53; Cal. Political Code 1872, § 3945; Cal. Stat. 1919, c. 470, § 20, p. 877; Cal. Political Code 1923, § 3927; Cal. Stat. 1923, c. 160, §20, p. 343; Cal. Govt. Code §23119; Cal. Stat. 1947, c. 424, p. 1055.
  See generally, Juridical Regime of Historic Waters, Including Historic Bays, U. N. Doc. A/CN.4/143, ¶¶ 80-105 (1962).
  The United States Attorney for the Southern District of California participated as an amicus curiae in the Stralla case and supported the position of California. We do not consider this action so significant as to foreclose the United States in the controversy before us. Compare the discussion of actions taken by the Secretary of the Interior in United States v. California, 332 U. S. 19, 39-40.
  See, e. g., 99 Cong. Rec. 2697 (remarks of Senator Cordon); Senate Hearings 1344-1345,1353-1358,1374.
  See, e. g., Statement of Robert Moses and the discussion following it. Senate Hearings 137.
  The United States points by analogy to judicial interpretations of the Swamp Land Act of 1850, 9 Stat. 519, to the effect that it granted only those lands which were swamp at the date of its passage. However, the terms of that Act were specific: “. . . those swamp and overflowed lands . . . which shall remain unsold at the passage of this act, shall be, and the same are hereby, granted . . and it granted lands sovereignty over which had never been thought to change because the nature of the land changed.