ROSE, Justice.
In this appeal we are asked to examine the effect of deed and contract language in order to resolve an ownership-of-minerals issue.
FACTS
On April 10,1940 the Federal Land Bank of Omaha, Nebraska entered into a contract for deed with appellant Maurice Williams, pursuant to which it agreed to transfer [622]*622ranch land titles to him upon payment of the purchase price. On December 28, 1954, the Land Bank delivered its warranty deed containing the following language.
“ * * * [EJxeepting and reserving an undivided one-half interest in all oil, gas, and mineral rights in and under the balance of the land for a period of 20 years from the 10th day of April, 1940, and as long thereafter as oil, gas, or other minerals continue to be produced therefrom or said property is being so developed or operated”.1
On October 27, 1949 Mr. Williams executed a contract for warranty deed with appellee Joseph H. Watt, undertaking to convey and, by deed dated December 7, 1956, did convey an undivided two-thirds interest to Joseph H. Watt and an undivided one-third interest to Robert E. Watt in certain of the lands which had been included in the Land Bank transaction. The contract and deed contained this provision:
“Excepting and reserving to the first party [Williams], his heirs, successors and assigns, all of the oil, gas and mineral rights running with said lands and to which he is entitled under the present ownership of said lands, and which have not been reserved to the United States or heretofore have been reserved or conveyed by previous owners and as may show of record * *
As can be seen, this exception was effected before the base term of the 20-year-or-production condition in the first deed had expired.
The only minerals or interest in mineral rights with which this appeal has any concern whatsoever have to do with those which the Land Bank excepted from its grant. It is certain rights which pertain to these minerals that Williams asserts he withheld from his subsequent transfer of real property to the Watts. It is conceded that the half of the minerals which were not excepted by the Land Bank were excepted from the deed from Williams to Watts and the Watts make no claim to these minerals.
On April 10,1960, (20 years from the date of the agreement between the Land Bank and Williams) there had been no production of oil, gas or other minerals from the lands and therefore the Federal Land Bank exception no longer burdened the controversial mineral interest. The trial court held that the disputed half of the minerals became the property of the Watts in fee simple absolute when the contingency expired.
We will reverse, holding that by expressly excepting from the Williams-Watt contract for deed and deed,
“all of the oil, gas and mineral rights * * to which he is entitled under the present ownership of said lands, and which have not been * * * heretofore * * * reserved or conveyed by previous owners * * *”,
the parties intended to and did withhold from the grant to the Watts a vested remainder. This remainder was owned by Williams at all times following the Land Bank-Williams transaction until the minerals themselves were automatically transferred to him upon the expiration of the 20-year contingency, no other oil, gas or other minerals then having been produced. When the condition contemplated by the 20-years-or-production provision in the Land Bank contract for deed and deed expired, the minerals became the property of Williams in fee simple by operation of law and thus did not either remain with the Land Bank by reason of any rule against perpetuity proscriptions,2 nor did they follow the land to its ownership in the Watts.
[623]*623ISSUE
The appellant Williams describes the issue for our resolve as follows:
“Did the District Court err in holding that the Appellees-Watts were the owners of 50% of the mineral rights in the subject real property despite the facts that: (1) Both Appellant-(Seller) Williams and Appellees-(Buyer) testified that it was their intent at the time of the sale of this property for all minerals to be reserved to Appellant; (2) the deed on its face reserves all of the minerals to Appellant Williams.”
The Court’s Identification of the Relevant Questions
We view the essential questions for consideration to be these: When Williams agreed to sell and did sell the land to the Watts in 1949 with delivery of deed in 1956, and, given the fact that the Land Bank’s exception of one-half of the minerals was not to terminate until 1960 or until oil, gas or other minerals ceased to be produced, what was the nature and what were the characteristics of the mineral interest or estate that the Federal Land Bank had excepted from its grant to Williams? What present and/or future interest or interests in these minerals did Williams possess after the conveyance from the Land Bank but prior to the expiration of the condition — if any? If, following the Land Bank’s exception from its grant, Williams was then possessed, or at some later time was to be possessed, of some sort of mineral interest or estate which he attempted to withhold when he conveyed the land to the Watts, was this such an interest as he then possessed and could lawfully withhold? Finally, did the minerals which were excepted by the Land Bank from its conveyance to Williams ultimately pass to the Watts upon the expiration of the term contemplated by the 20-year-or-production exception — as the trial court held — or did they remain the property of the Land Bank for the reason that the conveyance was void as being in violation of the rule against perpetuities, supra n. 2 — or did the minerals then become the property of Williams in fee simple by reason of the purported exception language which is contained in the deed to the Watts?
Introduction
By way of introduction to the deci-sional aspects of this opinion, it is appropriate to make this observation: All participating justices are secure in their interpretation of the Williams-Watt contract to the effect that it was the intent of these parties that Williams would come into ownership of the remaining disputed minerals when the condition contained in the Land Bank-Williams contract and deed no longer encumbered them. We consider the overriding obligation of this court to be to give effect to this intention of the parties — if that is possible. In fulfilling this obligation, the majority and the concurring justice reach the same result, but, in traveling through the complicated maze of future-interest concepts, we disagree about the labeling of the interest held by Williams as we all undertake to give effect to the intention of the parties. The majority of the justices hold that, contemporaneous with the execution of the Land Bank contract for deed and deed to Williams, Mr. Williams was possessed of a vested remainder. Justice Thomas, on the other hand, would identify Williams’ interest as an executory interest.
The majority take issue with the executo-ry-interest theory for the reason that the Wyoming statute (n. 2, supra) which adopts the rule against perpetuities would be violated under this concept. Justice Thomas objects to the majority position because he finds the law to be that there can be no remainder after an estate in fee simple determinable,3 which estate we all hold to be the interest which the Land Bank possessed in the disputed minerals prior to the expiration of the condition.
The majority concede the historical viability of Justice Thomas’ objection, but find [624]*624the modern law to be to the contrary — i.e., that a remainder can, in circumstances such as those which confront us here, follow a limited or qualified fee and may be excepted from a subsequent grant prior to the expiration of the qualification. On this issue, Gray, The Rule Against Perpetuities, 4th Ed., § 114, p. 108, n. 3, says that the concept which holds that there can be no remainder following a fee
“must be regarded, under modern conditions at least, as purely artificial * *
Thus, in more recent times, the rule against the possibility of an estate remaining after a fee is thought about as an historical anachronism. Indeed, were it not for the per-petuities problem discussed infra, it would not be necessary to distinguish between ex-ecutory interests and remainders.
In 28 Am.Jur.2d Estates § 197, “Distinctions — generally; from executory interest,” p. 341, the text undertakes to distinguish remainders and executory interests and comes to this conclusion:
“ * * * Most of the litigation involving remainders, vested and contingent, and executory interests, has been concerned with such questions of construction. Once the question of construction is settled, however, the further question of the technical designation of the future interest — whether it is a remainder or an ex-ecutory interest and, if a remainder, whether it is vested, vested subject to being divested, or contingent — is one of decreasing significance. There is a tendency to disregard the historical distinctions between contingent remainders and executory interests, and some- modern statutes in effect abolish the practical distinctions between them. Also, there is a rule that a limitation will be construed as creating a remainder rather than an executory interest if such can be done consistently with other rules of law.” (Emphasis added.)
Broadly speaking, executory interests or limitations are no longer distinguished from remainders but are grouped with them as future estates, 28 Am.Jur.2d Estates § 337, pp. 541-544. Justice Cardozo said in Doctor v. Hughes, 225 N.Y. 305, 122 N.E. 221, 222 (1919):
“ * * * Executory limitations are no longer distinguished from remainders, but are grouped with them as future estates (Real Prop.Law, §§ 36,37; Tilden v. Green, 130 N.Y. 29, 47, 28 N.E. 880, 14 L.R.A. 33, 27 Am.St.Rep. 487), and deeds, like wills, must be so construed as to effectuate the purpose of the grantor (Real Property Law, § 240, subd. 3).”
The Land Bank’s Estate
By reason of its exception, the Bank owned a fee simple defeasible estate in one-half of the minerals
We have said that:
“Oil and gas, while in situ, are part of the realty; part of the corpus of the land.” State ex rel. School Dist. No. 1 in Weston County v. Snyder, 29 Wyo. 163, 212 P.2d [P.] 758, 762 (1923).
See Burnell v. Roush, Wyo., 404 P.2d 836 (1965), and Denver Joint Stock Land Bank of Denver v. Dixon, 57 Wyo. 523, 122 P.2d 842, 140 A.L.R. 1270 (1942).
In Denver Joint Stock Land Bank of Denver v. Dixon, supra, we affirmed the district court’s decision, which held that the royalty interest was real and not personal property. See also State ex rel. Cross v. Board of Land Commissioners, 50 Wyo. 181, 58 P.2d 423 (1936), and Picard v. Richards, Wyo., 366 P.2d 119 (1961), where it was held that a conveyance or reservation of a mineral interest gave title to oil in place.
A landowner has the power to create separate interests in oil and gas by grant or exception, they being leasehold, mineral and royalty interests.4 It follows that he may create such interests for years, for life, or in fee. See 1A Summers Oil and Gas, Ch. 6, Landowner’s Powers and Liabilities, § 136 —Nature of the Legal Interest in Oil and Gas Created by Deed, Exception or Reservation. See also, Goodson v. Smith, 69 Wyo. 439, 243 P.2d 163, reh. denied 244 P.2d [625]*625805 (1952). See Krug v. Reissig, Wyo., 488 P.2d 150 (1971), where we recognized a life estate in the minerals.
In a conveyance excepting the minerals from the grant, we said in Ohio Oil Co. v. Wyoming Agency, 63 Wyo. 187, 179 P.2d 773, 774-775 (1947):
“ * * * It is admitted that a severance of the mineral estate from the surface estate was effected by this conveyance. See Tiffany on Real Property (3d ed.) § 587; Lindley on Mines (3d ed.) §§ 9,812; cases cited in State ex rel. Cross v. Board of Land Com’rs, 50 Wyo. 181, 200-203, 58 P.2d 423, 429, 430. 62 P.2d 516. The mineral estate, after severance, is often called the ‘mineral fee’ (see Dabney-Johnston Oil Corp. v. Walden, 4 Cal.2d 637, 650, 52 P.2d 237, 243) * * * »
In State ex rel. Cross v. Board of Land Commissioners, 58 P.2d at 430, we referred, with approval, to a case citing Thompson on Real Property, where that author said:
“ ‘ “Since minerals in place are part of the land, the owner of the fee in the land has the absolute right of property in the mines and quarries beneath the surface (citing cases), and all the mineral substances, while thus in place, are things of a real, and not a personal character (citing cases). As we have seen, that part of the land consisting of minerals, or specified minerals, may become the subject of separate ownership by grant of the minerals by the owner of the land, or by a grant of the land with an exception of the minerals, and in either case an estate in fee simple is created in the minerals, as corporeal hereditaments. (Citing cases).” ’ [Barlow v. Security Trust & Savings Bank, 197 Cal. 263, 240 P. 19, quoting from 1 Thompson on Real Property, § 87.]”
In Summers Oil and Gas, supra, the author says:
“Separate estates or interests in oil and gas may be created for a definite term of years and as long thereafter as oil or gas is produced from the land in paying quantities.” (Emphasis added.) § 136, supra, p. 282.
As has been noted, the Land Bank’s exception was subject to a contingency for an indefinite term, i.e. 20 years and as long thereafter as oil and gas are produced therefrom. Since mineral and surface estates may be severed one from the other under the circumstances of this case, it follows that the Federal Land Bank’s exception severed the minerals from the land conveyed to Williams.
In his brief and argument, appellant Williams reaches the erroneous conclusion that the contingency contained in the Land Bank grant to Williams expressed a term for years which was not a freehold interest.5 From this faulty term-for-years assumption, it is reasoned that, since it was necessary that the fee be held to reside in someone, it must be in Williams and therefore he could and did reserve it when he executed the warranty deed to the Watts. Even though this court and Williams come to the same ultimate result — i.e., that Williams owned an exceptable interest which he could and did except — we do not travel the same path in order to arrive there.
Appellant Williams represents that at the time of the Land Bank’s deed to him
“ * * * 100% of the minerals became vested in Maurice Williams, subject to a twenty (20) year term interest in 50% of the minerals held by the Federal Land Bank.”
He goes on to say:
“The Federal Land Bank reserved an undivided one-half interest in the minerals for a period of twenty years. ‘Every estate which must expire at a period certain and prefixed, by whatever words created, is an estate for years.’ 2 Blackstone, Commentaries on the Common Law, 143, quoted in Ralston Steel Car Company v. Annie M. Ralston, [112 Ohio [626]*626St. 306], 147 N.E. 513, 516, 39 ALR. 334, 338 (1925). The interest reserved by the Federal Land Bank is an estate for years. An estate for years is not a free-hold interest. King v. White, 499 P.2d 585. (Wyo.1972).
“Since the Federal Land Bank reserved only an estate for years in 50% of the minerals, seizen to 100% of the minerals had to be vested in someone at the time of the conveyance from the Federal Land Bank to Maurice Williams. Because a term interest is not a freehold interest, the minerals could not have been vested in the Federal Land Bank. All of the mineral rights were vested in Maurice Williams.
“Maurice Williams had a present vested interest in 100% of the minerals, subject to a twenty-year estate for years in 50% of the minerals reserved by the Federal Land Bank. See Bergin and Haskel, Preface to Estates and Land and Future Interest, p. 41 (Foundation Press 1966). “Maurice Williams owned the entire mineral estate. He owned 50% of the minerals in fee simple absolute, and 50% of the minerals in fee subject to an estate for years. On April 10,1960, when the term of years held by the Federal Land Bank expired, Maurice Williams became owner in fee simple absolute of 100% of the minerals in the subject lands.”
The exception in the Land Bank’s grant to Williams did not describe an estate for years and, during the life of the contingency, a determinable fee interest in the minerals did in fact reside in the Land Bank and the fee estate was not held by Williams.
The term of the contingency was not definite as the appellee contends. Had there been production within the base period, the Federal Land Bank’s right to save, keep and dispose of its one-half of the disputed minerals would have continued for such a period of time as could only be considered to be beyond ascertainment when either of the deeds with which this appeal is concerned is executed and delivered. The appellant was therefore in error in making the assumption that the contingency was for a term of years and that for this reason fee title to 100% of the minerals was in Williams at all times following the grant from the Federal Land Bank.
As we have previously noted, this court has on other occasions inquired into the status of an oil and gas lease which conveys such a mineral interest to its lessee as that which is retained by a grantor who excepts minerals from a grant by deed. In Torgeson v. Connelly, Wyo., 348 P.2d 63, 68-69 (1959), where the court was concerned with an oil and gas operating agreement with a primary term of 20 years and
“ ‘ * * * so long thereafter as oil and gas and hydrocarbon substances are produced in commercial quantities,’ ”
the agreement undertook to grant the exclusive right to drill in accord with a federal lease. The court was of the opinion that
“ * * * it in effect conveys a portion of the lease or the rights thereunder and constitutes real property.”
We held in Torgeson, supra, that leases for a limited term are personalty, while leases for an indefinite period are realty. In that same opinion we said, in referring to our holding in Denver Joint Stock Land Bank of Denver v. Dixon, supra:
“ * * * We noted Dutton v. Interstate Investment Corporation, Cal.App., [19 Cal.2d 65], 113 P.2d 492 and Arrington v. United Royalty Co., 188 Ark. 270, 65 S.W.2d 36, 90 A.L.R. 765, as holding that leases for a limited term of years had been held to be personalty * * * ” 348 P.2d at 68,
but that
“ * * * [t]he Dutton and Arrington cases both held that leases for an indefinite term had been considered to be realty, the latter indicating that the term of the lease is indefinite if the contract provided ‘and so long as oil and gas is produced.’ ” (Emphasis added.) 348 P.2d at 69.
It was said in Arrington v. United Royalty Co., 188 Ark. 270, 65 S.W.2d 36, 38, 90 A.L.R. 765 (1933):
“ * * * It seems, also, that whether the royalty, when severed from the reversion, [627]*627is to be deemed real or personal property, depends upon the duration of the lease. If the oil and gas lease is for a term of years expiring at a certain time, it is a chattel real, and the severed royalty would be personal property; but, where the lease may endure for an Indeterminate period, it creates an estate in the nature of a qualified fee, and the royalty reserved would be an interest in realty. “We have held that leases given for a definite period in which exploration and discovery of the mineral might be made, to continue as long thereafter as oil and gas is produced conveys not merely a license but an interest and easement in the land itself. Standard Oil Co. v. Oil Well Salvage Co., 170 Ark. 729, 281 S.W. 360; Clark v. Dennis, 172 Ark. 1096, 291 S.W. 807; Henry v. Gulf Refining Co., 176 Ark. 133, 2 S.W.(2d) 687; and Henry v. Gulf Refining Co., 179 Ark. 138, 15 S.W.(2d) 979.” (Emphasis added.)
Accordingly, the exception for 20 years and as long thereafter as oil, gas or other minerals continue to be produced therefrom constituted a real-property interest in the Land Bank.
There is no doubt but that such an exception as that contained in the Land Bank’s deed is acceptable to real property and to mineral and oil and gas law. The estate structured by such an exception is a base or determinable fee which is defeasible at the end of the base term or — in the event production is attained — when production ceases. The Restatement of the Law of Property calls it an “estate in fee simple determinable.” Restatement of the Law of Property § 44, p. 121.
“ * * * [A] ‘determinable,’ ‘qualified,’ or ‘base’ fee is an estate limited to a person and his heirs, with a qualification annexed to it providing that such estate must determine whenever that qualification is at an end. Because the estate may last forever, it is a fee; and because it may end on the happening of an event, it is called a ‘determinable or qualified fee.’ ” 28 Am.Jur.2d Estates § 22.
It was said in United States v. Union Pacific Railroad Company, 230 F.2d 690, 694 (1956), rev’d on unrelated grounds:
“Generally the terms ‘limited’, ‘determinable’, ‘qualified’, or ‘base’ fee, as applied to the title of real estate, are used synonymously. Because of the possibility that it may endure forever, the owner of such an estate, so long as it exists, even though title may revert upon the happening of a condition, has the same rights as an owner in fee simple and may remove underlying minerals. 19 Am.Jur., Estates, Secs. 28, 30, 31; 31 C.J.S., Estates, §§ 9, 10; Restatement of Property, Sec. 193, Comment (h); United States v. Illinois Central R. Co. [D.C., 89 F.Supp. 17], supra; Frensley v. White, 208 Okl. 209, 254 P.2d 982; Davis v. Skipper, 125 Tex. 364, 83 S.W.2d 318; Johnson Irrigation Co. v. Ivory, 46 Wyo. 221, 24 P.2d 1053; D.C., 126 F.Supp. 646.”
The existence of an estate in fee simple determinable requires the presence of special limitations. Restatement of the Law of Property, § 44, p. 121. The term “special limitation” denotes that part of the language of a conveyance which causes the created interest automatically to expire upon the occurrence of a stated event. Restatement of the Law of Property, § 23, p. 55. An estate in fee simple determinable may be created so as to be defeasible upon the occurrence of an event which is not certain ever to occur. Restatement of the Law of Property, § 44, p. 125.
As we have seen, we approved the Arrington v. United Royalty rule in Denver Joint Stock Land Bank of Denver, supra, where the Arrington court said:
“ * * * [W]here the lease may endure for an indeterminate period it creates an estate in the nature of a qualified fee * 65 S.W.2d at 38.
Chapter 4 of the Restatement of the Law of Property, pp. 117-118, provides:
“Introductory Note: An estate in fee simple defeasible is defined as an estate in fee simple which is subject to a special limitation, a condition subsequent, an ex-[628]*628ecutory limitation or a combination of these restrictions.
“The estate in fee simple subject to a special limitation is also designated as an ‘estate in fee simple determinable.’ It expires in accordance with its terms. It ends automatically upon the occurrence of the event stipulated in its limitation.”
In Baker v. Hugoton Production Company, 182 Kan. 210, 320 P.2d 772 (1958), the grant of a mineral interest from A to B carried the proviso that it was to be held by B for a term of twenty years and as long thereafter as oil, gas or either of them, are being produced from said land.
The court held that the instrument grants
“ * * * a base or determinable fee in the oil, gas and other minerals in place * 320 P.2d at 774.
In Wilson v. Holm, 164 Kan. 229, 188 P.2d 899, 904 (1948), it was said:
“ * * * [I]t should be stated that in this state a deed, conveying oil and gas in place for a fixed term of years and so long thereafter as either or both are produced in paying quantities, creates a base or determinable fee and that title to the estate so created vests immediately upon the execution and delivery of such an instrument but remains defeasible in the event of cessation of production, [citing a Kansas case].”
In the case at bar, the Land Bank’s exception carried no restriction as to use— only a condition which made it subject to the possibility of defeasance. It was, therefore, a determinable qualified or base fee.
Characteristics of a Base or Determinable Fee
“A determinable or qualified fee has all the attributes of a fee simple, except that it is subject to be defeated by the happening of the condition which is to terminate the estate.” 28 Am.Jur.2d Estates, Determinable Qualified or Base Fee, § 26, Attributes and incidents — generally: rights of holder, p. 103.
We said in Johnson Irrigation Co. v. Ivory, 46 Wyo. 221, 24 P.2d 1053, 1058 (1933):
“We may also agree that a grantee who takes a limited or qualified fee,[6] liable to be defeated * * * may, while the estate continues, have the same rights and privileges as an owner in fee simple.”
In the Restatement of the Law of Property § 49, p. 170, it is said:
“The privilege of the owner of a possesso-ry estate in fee simple defeasible to use the land [minerals in the instant case] is identical with that of an owner of a pos-sessory estate in fee simple absolute except that the privilege is limited by a duty not to commit waste.”
The Restatement goes on to say:
“Except as modified by the terms of the limitation creating an estate in fee simple defeasible, the power and the privilege of the owner of such an estate to create an interest in the affected land are identical with those of an owner having an estate in fee simple absolute therein, but all interests so created are subject to the defeasibility which existed as to the estate of the transferor.” Restatement of the Law of Property § 50, p. 173.
We conclude that the Federal Land Bank, in excepting one-half of the minerals from the grant to Williams
“ * * * for a period of 20 years * * * and as long thereafter as * * * minerals continue to be produced * * * ”
was possessed of an estate in fee simple in the excepted minerals subject to the qualification expressed in the deed. It was during the life of the qualification that Williams conveyed the land to the Watts and Williams did not hold fee title to the minerals during the life of the contingency. That freehold interest resided in the Federal Land Bank, subject to the contingency.
[629]*629Williams’ Interest — A Vested Remainder
After the grant from the Land Bank, Williams’ interest in the disputed minerals is properly identified as a vested remainder.
I
Characterization of various interests based upon historical concepts
In its deed to Williams, the Land Bank excepted:
“ * * * an undivided one-half interest in all oil, gas, and mineral rights in and under the balance of the land for a period of 20 years * * *, and as long thereafter as oil, gas, or other minerals continue to be produced therefrom or said property is being so developed or operated * * *.”
As has been noted, the interest held by the Land Bank following the grant is properly identified as a fee simple determinable. Once it is established that the Land Bank withheld a determinable fee in the mineral estate, classical concepts of property law (absent statutory rule against perpetuities proscriptions), disassociated from the unique characteristics of mineral law, would indicate that the interest created in Williams be identified as an executory interest. Given historical guidelines, the only other designations for Williams’ interest are a possibility of reverter and a remainder.
It is conceded that Williams’ interest cannot be labeled a possibility of reverter, because a possibility of reverter is such an interest as is retained by the transferor, following the conveyance of a fee simple determinable. Simes and Smith, The Law of Future Interests, 2d Ed., § 281 (1956); 28 Am.Jur.2d Estates § 22; Restatement of the Law of Property, § 154(3) (1936). Since the disputed interest was transferred to Williams, rather than retained by the Land Bank, it cannot properly be designated a possibility of reverter.
Under antiquated historical concepts it could be — and in Justice Thomas’ concurring opinion is — argued that a remainder is likewise an inappropriate designation of Williams’ interest for the reason that a remainder cannot follow a fee. Simes and Smith, supra, § 103; 28 Am.Jur.2d Estates § 196; Restatement of the Law of Property, § 156(2). The justification for this rule is that once the owner of an estate in fee simple conveys his estate in fee simple, there is nothing left to constitute a remainder. Bergin & Haskill, Preface to Estates in Land and Future Interests (1966), p. 72.
In Simes and Smith, The Law of Future Interests, 2d Ed., § 103, the authors say:
“The second characteristic [of a remainder] is that there can be no remainder after a fee simple. This is true even though the fee simple be subject to a special limitation. This is explainable only on historical grounds. All fees simple were regarded as of the same quantum and infinite duration. Hence it was thought that, when the fee simple had been given, no ‘remnant’ could be left to grant or devise.”
Once the possibility of reverter and the remainder have been ruled out as appropriate labels for Williams’ interest, it follows from these traditional principles that Williams should be held — on historical grounds — to have possessed an executory interest in the mineral estate excepted by the Land Bank. The Restatement of the Law of Property, § 158, says:
“(1) An executory interest is any future interest created by an executory limitation (defined in § 25).
“(2) Executory interests as defined in Subsection (1) include all future interests, other than remainders * * * which can be created in a transferee.”
Section 25 of the Restatement of the Law of Property provides in part:
“ * * * [T]he term ‘executory limitation’ denotes that part of the language of a conveyance, by virtue of which
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“(b) an estate in fee simple determinable, * * * concurrently with its expiration, is to be succeeded forthwith by another interest in a person other than the conveyor or his successor in interest.”
The exception by the grantor of a determinable fee and the resulting interest in the [630]*630grantee are discussed in 28 Am.Jur.2d Estates § 37:
“By reservation or exception.
“While a fee simple determinable is created by the grant of the fee simple determinable to the grantee, thereby reserving the possibility of reverter to the grantor, where an attempt is made to reverse the positions of the grantor and grantee by excepting a determinable fee from the grant, the grantor is held to take a determinable fee, but the grantee takes a future interest in the nature of a springing use, rather than a possibility of reverter, which future estate may, unlike a possibility of reverter, be subject to the rule against perpetuities.”
An executory interest, by definition, does not vest so long as it remains a future interest. Simes and Smith, supra, § 221. Consequently, all executory interests are subject to invalidation by the rule against perpetuities. Gray, The Rule Against Perpetuities, 4th Ed. (1942), § 317. To say that a rule-against-perpetuities result is contrary to the intentions of the parties is of no avail, because the rule against perpetuities always operates to frustrate the parties’ intentions.
Despite the foregoing conclusion that the exception by the grantor of a determinable fee may subject the granted ex-ecutory interest to problems with the rule against perpetuities, only a few courts have found such interests to be void. Walker v. Marcellus & O.L. Ry Co., 226 N.Y. 347, 123 N.E. 736 (1919); Victory Oil Co. v. Hancock Oil Co., 125 Cal.App.2d 222, 270 P.2d 604 (1954); 2 Williams and Meyers, Oil and Gas Law (1981), § 335, pp. 177-180. Many cases simply assume the validity of these interests without any discussion of the rule against perpetuities. 2 Williams and Meyers, supra at 180, and cases cited therein. A recent Texas case found that in such situations the law implies that the grantor conveyed his entire estate to the grantee, who then regranted a determinable fee to his grantor. This fictitious regrant resulted in a possibility of reverter in the original grantee which was valid under the rule against perpetuities. Bagby v. Bredthauer, Tex.Civ.App., 627 S.W.2d 190 (1981). A number of other courts, while not dealing directly with an excepted determinable fee, have held that conveyances in the commercial context are exempt from the rule against perpetuities. Camerlo v. Howard Johnson Company, 545 F.Supp. 395 (W.D.Pa.1982); Forderhause v. Cherokee Water Company, Tex.Civ.App., 623 S.W.2d 435 (1981), rev’d on other grounds 641 S.W.2d 522, 526 (1982); Producers Oil Company v. Gore, Okl., 610 P.2d 772 (1980).
In view of the fact that the rule against perpetuities is embodied in a statute7 and in the Constitution8 in Wyoming, this court is without authority to carve out an exception to the constitutional and statutory provision or to circumvent the Constitution and statute through the inference of a fictitious regrant or by the utilization of any other fictitious device — and it is at this juncture that the majority parts company with Justice Thomas.
In light of Justice Thomas’ concurring opinion, it is well to pause here and further explore the perpetuities problem. It is worth noting that a holding designating Williams’ interest as “executory” and thus violative of the rule against perpetuities would have the result of finding the Land Bank to be possessed of the disputed minerals — a result which was not contemplated either by the parties or the Land Bank.
Wyoming has adopted the common-law rule against perpetuities through § 34^1-139, supra n. 2. This statute implements Art. 1, § 30 of the Wyoming Constitution. See n. 8. In any effort to circumvent the rule against perpetuities by fiction or otherwise, or to carve out an exception to the rule — for any reason — we are first off confronted with well-established rules having [631]*631to do with the necessity to give effect to statutory and constitutional provisions.9
We said in Yeik v. Department of Revenue and Taxation, Wyo., 595 P.2d 965, 968-969 (1979):
“ * * * It is the duty of courts to endeav- or by every rule of construction available to ascertain the meaning of and give full force and effect to the legislative product. 1A Sutherland, Statutory Construction, § 21.16 (fn. 2) (1972). The legislature will not be presumed to intend futile things. De Herrera v. Herrera, Wyo. 1977, 565 P.2d 479; See West’s Digest System, Statutes, Key Number 212.4.”,
and in McGuire v. McGuire, Wyo., 608 P.2d 1278, 1285 (1980), we said:
“It is this court’s obligation to make sense out of a statute and give full force and effect to the legislative product. Yeik v. Department of Revenue and Taxation, Wyo.1979, 595 P.2d 965. In construing statutes, the intention of the law-making body must be ascertained from the language of the statute as nearly as possible. Wyoming State Treasurer v. City of Casper, Wyo.1976, 551 P.2d 687. We must not give a statute a meaning that will nullify its operation if it is susceptible of another interpretation.”
With respect to the construction, operation and enforcement of constitutional provisions, we have said in Zancanelli v. Central Coal & Coke Co., 25 Wyo. 511, 173 P. 981, 991 (1918):
“The general principles governing the construction of statutes apply to the construction of Constitutions. * * * And the fundamental purpose in such construction is to ascertain the intent of the framers and the people who adopted it, and give effect thereto.”
In Schaefer v. Thompson, 240 F.Supp. 247, 253 (1964), it was said:
“ * * * In construing constitutional provisions, the fundamental purpose is to give effect to their purpose and intent. Courts will not ignore the general spirit of the instrument.”
Since the rule against perpetuities is applicable to executory interests, and since Wyoming’s statute § 34-1-139, adopts the rule, the only question — with respect to whether the interest at hand should be designated as executory — is whether, under the exception by the Land Bank, the interest would offend the statutory rule. In this case, we must hold it would. As we have said, one of the characteristics of the execu-tory interest is that it does not vest until possession. Under the Land Bank contingency language, there is no way to know that the interest in question will vest
“not later than twenty-one (21) years after some life in being at the creation of the interest * * *” § 34-1-139,
and thus, if identified as executory, the interest is void as being in violation of the rule against perpetuities and — in which case — the intentions of the parties would be thwarted because fee title to the disputed minerals would remain in the Land Bank.
II
Characterization of the interests created by the grant based on the attributes of the mineral estate
The discussion in Part I of this topic focuses exclusively on historical concepts [632]*632which are applicable to the interests created by deed in the Land Bank and Williams. If we were to temper these historical concepts by considering the unique attributes of a mineral estate, then the interest that Williams held following the Land Bank grant authoritatively and logically may be designated as a “vested remainder.”
As we have said, the Land Bank withheld a present fee interest in the mineral estate for 20 years and so long thereafter as production continues. An analogous example in the surface estate context would be a grant of Blackacre from A to B, reserving to A a present fee interest in Blackacre so long as no gambling occurs on the premises. A would own a fee simple determinable in Blackacre and B would have an executory interest. However, B’s interest would be void under the rule against perpetuities, with the result that A would possess Black-acre in fee simple absolute.
The interest in B in the above example is typical of the vast majority of executory interests. It is limited upon a condition precedent not certain ever to be fulfilled and it follows an estate in fee simple not certain to end. Gambling may never occur on Blackacre. Jones, The Rule Against Perpetuities as it Affects California Oil and Gas Interests, 7 U.C.L.A.Law Rev. 261, 265 (1960). In contrast, the event upon which Williams is to take the mineral estate is one certain to occur. Production of minerals will eventually cease; the only unknown is the time of cessation. When production of minerals ceases, the estate in the Land Bank automatically terminates. There is no doubt that the Land Bank’s estate in the excepted minerals will eventually come to an end. See Jones, supra at 265-266.
Remainder Interest
Since the mineral estate in Williams differs significantly from the typical executo-ry interest in Blackacre, it makes sense to call it something other than an executory interest. It is undisputed that the interest retained by the Land Bank is of a lesser duration than its original estate. The Land Bank excepted an estate which will eventually terminate, either because production was halted (for whatever reason) or the recoverable, minerals were exhausted. Thus, some interest will remain after the estate excepted by the Land Bank expires and it is that interest which was conveyed to Williams. If Williams’ interest satisfies all of the other requirements of a remainder, it should be possible, conceptually, to call it a remainder. According to Simes and Smith, supra, § 103, the other characteristics of a remainder are:
1. The remainder is always created by express limitation or by implication of fact and by the same instrument which creates the preceding estate.
2. At the time of its creation, the remainder must be capable of taking effect in possession at the expiration of the preceding estate, although it does not terminate the preceding estate.
3. The remainder does not normally divest or cut short the preceding posses-sory estate.
Williams’ interest was created by express limitation in the same deed that created the preceding estate in the Land Bank, and he stands ready to take possession upon the expiration of the Land Bank’s estate. In addition, the estate in the Land Bank will terminate naturally upon the exhaustion of recoverable minerals or the cessation of mineral production for whatever cause. With only a little exercise of property-law imagination, the fee simple determinable in the mineral estate may be analogized to the ordinary life estate. When the minerals “die” (the passage of 20 years or the cessation of production), the present estate in the Land Bank expires and passes automatically to Williams. In light of the above discussion, it is therefore reasonable and proper to identify an interest in a mineral estate following a determinable fee as a remainder without doing impermissible damage to traditional common-law concepts.
Vested Versus Contingent
If Williams’ interest is properly identified as a remainder, the next question [633]*633is: What kind of a remainder did Williams possess over and above the interest excepted by the Land Bank?
As discussed above, the event upon which Williams will take is certain to occur. The only unknown is when the event will occur. In 28 Am.Jur.2d Estates § 242, p. 396, it is said:
“The broad distinction between vested and contingent remainders is this: In the first, there is some person in esse known and ascertained, who, by the will or deed creating the estate, is to take and enjoy the estate, and whose right to such remainder no contingency can defeat. In the second, it depends upon the happening of a contingent event, whether the estate limited as a remainder shall ever take effect at all. The event may either never happen, or it may not happen until after the particular estate upon which it depended shall have been determined, so that the estate in remainder will never take effect.”
A remainder is not rendered contingent merely because the time at which the estate will become possessory is uncertain. Section 243 of 28 Am.Jur.2d Estates provides:
“There is a definite distinction between the uncertainty which makes a remainder contingent and the uncertainty of the estate’s ever taking effect in possession, which is incident to even a vested remainder. In a contingent remainder, the right to the estate is uncertain, while in a vested remainder, the time of possession and enjoyment being deferred, there is an uncertainty as to whether the estate will ever be enjoyed in possession. It is in this respect only that a vested remainder is contingent and expectant; for, unlike a contingent remainder, it is vested in right, and the remainderman has an immediate right of future enjoyment. Although it may be uncertain whether a remainder will ever take effect in possession, it will nevertheless be a vested remainder if the interest is fixed. It is the uncertainty of the right of enjoyment, and not the uncertainty of its actual enjoyment, which renders a remainder contingent and distinguishes it from a vested remainder.”
See also Jones, supra at 266-267.
Bergin and Haskell, Preface to Estates in Land and Future Interests, supra at 71, identify two requirements for a vested remainder: (1) that there is no condition precedent to the future interest becoming a present estate other than the natural expiration of the prior life estate [or fee tail] and (2) that it is theoretically possible to identify who would get the right to possession if the prior estate should end at any time. Since the condition upon which Williams will take a present estate is certain to occur, and since the condition is the natural expiration or “demise” of the prior mineral estate, then Williams’ estate is vested rather than contingent. Since Williams’ estate was vested at the time of its creation, it is valid under the rule against perpetuities.
Conclusion
We of the majority are, by this discussion, forced to the observation that we now find ourselves playing games with respect to these future-interest brain twisters — games in which only real-property professors should be permitted to indulge themselves. Suffice it to say, for purposes of disposing of this appeal, that a limitation will be construed as creating a remainder rather than an executory interest if such can be done consistently with other rules of law. 28 Am.Jur.2d Estates § 197, p. 341. Certainly this may be accomplished here. If, on the other hand, we were not able to come to the conclusion which is reached by the majority in this case, we would not be able to give effect to what all justices acknowledge was the intent of the parties. This is so because the interest remaining after the determinable fee would, if it were designated an executory interest, be in violation of the rule against perpetuities and therefore void. This would leave fee title absolute in the Land Bank — a result which would defeat the intent of all parties.
Williams’ interest, after the Land Bank exception, was a vested remainder which was exceptable from the grant to the Watts [634]*634and when the contingency in the Land Bank deed expired, the minerals became his in fee simple absolute.
Reversed and remanded for entry of an order which will give effect to this opinion.