Properly construed, we think the instrument in effect negatives any such intention. The legal significance of such terms as limitations, conditions subsequent, etc., to be found in leases and other instruments of conveyance will not be discussed since the nature of the same has been thoroughly considered and well stated in such authorities as W. T. Waggoner Estate v. Sigler Oil Co., 118 Tex. 509, 19 S.W.2d 27; Mon-Tex Corp. v. Poteet, Tex. Civ. App. 13 S.W.2d 211; Id., 118 Tex. 546, 19 S.W.2d 32; Ralph v. Magnolia Pet. Co., Tex. Civ. App. 95 S.W.2d 222, writ ref. It is perhaps unnecessary to point out specifically these characteristics of said conveyance or to make any general deductions or conclusions as to the legal effect thereof.

The most common attribute, therefore, of a lease contract, namely, the reversionary interest or possibility of reversion, is wholly absent. Danciger Oil Refining Co. v. Powell, 137 Tex. 484, 154 S.W.2d 632, 137 A.L.R. 408; Duhig v. Peavy-Moore Lumber Co., Inc., 135 Tex. 503, 144 S.W.2d 878, 879; Loomis v. Gulf Oil Corp., Tex.Civ.App., 123 S.W.2d 501; Hynson v. Gulf Prod. Co., Tex.Civ.App., 232 S.W. 873; Ralph v. Magnolia Petroleum Co., Tex.Civ.App., 95 S.W.2d 222. The lessee in an ordinary oil and gas lease is vested with "the privilege of exploiting the land for the production of oil and gas for a prescribed period."

The following decisions and authorities therein cited sustain these conclusions. Hines v. Hanover Co., Tex. Com.App., 23 S.W.2d 289; Leonard v. Prater, Tex.Com.App., 36 S.W.2d 216, 86 A.L.R. 499; Ralph v. Magnolia Petroleum Co., Tex.Civ.App., 95 S.W.2d 222; Cosden Oil Co. v. Scarborough, 5 Cir., 55 F.2d 634; Amerada Petroleum Co. v. Doering, 5 Cir., 93 F.2d 540, 114 A.L.R. 1385. Reversible error not appearing the judgment is affirmed.

In other words, it is the contention of appellants that when oil, gas or minerals are discovered that the grantor or its assignees would be entitled to a one-fourth of a one-eighth or one thirty-second royalty interest and not to a one-fourth mineral fee. This seems to us to be the correct interpretation of the said exception or reservation. Jackson v. Delaney, 67 W. Va. 309, 67 S.E. 795; Luman v. Davis, 108 Kan. 801, 196 P. 1078; Harris v. Cobb, 49 W. Va. 350, 38 S.E. 559, 21 Mor. Min. Rep. 263; Denver Joint Stock Land Bank of Denver v. Dixon, 57 Wyo. 523, 122 P.2d 842, 140 A.L.R. 1270; Douglas v. Douglas, 176 Okla. A.P.L. 238, 56 P.2d 362; Myers v. Hines, 149 Okla. 232; Cline v. Humble Oil Refining Co., 67 S.W.2d 911; Schlittler v. Smith, 128 Tex. 628, 101 S.W.2d 543; Gill v. Bennett, 59 S.W.2d 473; Ralph v. Magnolia Petroleum Co., 95 S.W.2d 222; 3 Summers Oil and Gas 349, Sec. 572. We maintain that the attempted reservation with reference to oil, gas and minerals in the deed executed by the grantee, the Great Southern Lumber Company, did not reserve any present interest in the oil, gas and minerals, but stated that under the reservation the said grantee would be entitled to participate in the said oil and minerals after the discovery of same. There has been no discovery of oil, gas or minerals in the land and we maintain that if the said reservation is valid it is to be construed as a perpetual non-participating royalty interest, the grantee not having reserved the right to participate in making future leases of such minerals or in rentals and bonuses.

The obligation of a lessee to develop as a reasonably prudent operator may be relieved by contract. Coats v. Brown, Tex.Civ.App., 301 S.W.2d 932; Warren v. Amerada Petroleum Corp., Tex.Civ.App., 211 S.W.2d 314; Simms Oil Co. v. Flewellen, 138 Tex. 63, 156 S.W.2d 521; Magnolia Petroleum Company v. Page, Tex.Civ.App., 141 S.W.2d 691; Cowden v. Broderick Calvert, Inc., 131 Tex. 434, 114 S.W.2d 1166, 117 A.L.R. 61; Ralph v. Magnolia Petroleum Company, Tex.Civ.App., 95 S.W.2d 222. Appellants' Point Two reads as follows:

(Emphasis added.) Ralph et al. v. Magnolia Petroleum Company et al., Tex.Civ.App., 95 S.W.2d 222 (writ refused); Cowden v. Broderick Calvert, Inc. et al., 137 Tex. 434, 114 S.W.2d 1166, 117 A.L.R. 61. The Ralph case involved a similar mineral deed to ours that was also in 'wildcat' territory and with identical provisions eliminating the company's obligation to drill or mine for the minerals and that any mining or drilling, both before or after production, shall be wholly at the option of Grantee. It was there urged that notwithstanding such provisions there was an implied obligation on the part of the company to explore, develop and produce the oil, gas and other minerals. The Court there quoted with approval from another authority in which the Supreme Court said: 'The Court * * * can declare implied covenants to exist only when there is a satisfactory basis in the express contracts of the parties which makes it necessary to imply certain duties and obligations in order to effect the purposes of the parties in the contracts made. Before a covenant will be implied in the express

Therefore, the usual covenant of reasonable development is implied and the trial court committed fundamental error in sustaining the demurrer on that ground." Cited as authorities to support this proposition are: Summers Oil Gas, Per.Ed., Vol. 2, page 355, § 411; Summers Oil Gas, Per.Ed., Vol. 2, pages 301-309, § 395; W. T. Waggoner Estate v. Sigler Oil Co., 118 Tex. 509, 19 S.W.2d 27; Thornton Oil Gas (Willis) pp. 268-9, § 154; Merrill's Covenants Implied in Oil Gas Leases, § 117, p. 279; Grubb v. McAfee, 109 Tex. 527, 531, 212 S.W. 464; Freeport Sulphur Co. v. American Sulphur Royalty Co., 117 Tex. 439, 454, 6 S.W.2d 1039, 60 A.L.R. 890; Texas Pacific Coal Oil Co. v. Barker, 117 Tex. 418, 6 S.W.2d 1031, 60 A.L.R. 936; Gulf Production Co. v. Kishi et al., 129 Tex. 487, 103 S.W.2d 965; Ralph v. Magnolia Petroleum Co., Tex. Civ. App. 95 S.W.2d 222; Cowden v. Broderick Calvert, 131 Tex. 434, 114 S.W.2d 1166, 117 A.L.R. 61; Rhoads Drilling Co. v. Allred, 123 Tex. 229, 70 S.W.2d 576; Stanolind Oil Gas Co. v. Barnhill, Tex. Civ. App. 107 S.W.2d 746; Cole Petroleum Co. v. United States Gas Oil Co., 121 Tex. 59, 41 S.W.2d 414, 86 A.L.R. 719; Brewster v. Lanyon Zinc Co., 8 Cir., 140 F. 801. The brief for appellee Stanolind Oil and Gas Company sets forth this proposition: "The subject matter of development of the Flewellen tract of land is controlled by express covenants contained in the lease of October 31, 1919, from Flewellen to Turner, thereby precluding the existence of an implied covenant."

Reference to the summary of pleadings hereinbefore made will disclose that in the paragraph stating lessee's obligation to drill offsets in the event of production on adjoining land, this language is used, "lessor agrees that all other development shall be at the discretion of the lessee." Appellee contends that the use of this language eliminates the obligation to reasonably develop the land that is usually implied, and that the word "discretion" as used in the lease is synonymous with the word option, citing Ralph v. Magnolia Petroleum Co., 95 S.W.2d 222, 231 (decided by this court) as being directly in point. With this view we cannot agree.