The primary question presented by this appeal is whether the Hofmann Forest is exempt from ad valorem taxation. The Onslow County case also presents the question as to whether the county, through procedural default, is precluded from collecting ad valorem taxes for the years in question, 1974 and 1975. An additional question in the Jones County case is whether the land has been properly valued for ad valorem tax purposes.
We first consider the exemption question.
The Foundation relies upon four statutes (G.S. 105-275(12), 105-278.4, 105-278.6, and 116-16) as alternative bases for its contention that the Hofmann Forest land is exempt from ad valorem taxes.
*335The first three of these statutes require that the property be used exclusively for one exempt purpose or another. The pertinent provisions of these three statutes are:
§ 105-275. Property classified and excluded from the tax base.— The following classes of property are hereby designated special classes under authority of Article V, Sec. 2(2), of the North Carolina Constitution and shall not be listed, appraised, assessed, or taxed:
* * *
(12) Real property owned by a nonprofit corporation or association exclusively held and used by its owner for educational and scientific purposes as a protected natural area. (For purposes of this subdivision, the term “protected natural area” means a nature reserve or park in which all types of wild nature, flora and fauna, and biotic communities are preserved for observation and study.) [Emphasis added.]
§ 105-278.4. Real and personal property used for educational purposes.— (a) Buildings, the land they actually occupy, and additional land reasonably necessary for the convenient use of any such building shall be exempted from taxation if:
(1) Owned by an educational institution (including a university, college, school, seminary, academy, industrial school, public library, museum, and similar institution);
(2) The owner is not organized or operated for profit and no officer, shareholder, member, or employee of the owner or any other person is entitled to receive pecuniary profit from the owner’s operations except reasonable compensation for services;
(3) Of a kind commonly employed in the performance of those activities naturally and properly incident to the operation of an educational institution such as the owner; and
(4) Wholly and exclusively used for educational purposes by the owner or occupied gratuitously by another nonprofit educational institution (as defined herein) *336 and wholly and exclusively used by the occupant for nonprofit educational purposes.
(b) Land (exclusive of improvements); and improvements other than buildings, the land actually occupied by such improvements, and additional land reasonably necessary for the convenient use of any such improvement shall be exempted from taxation if:
(1) Owned by an educational institution that owns real property entitled to exemption under the provisions of subsection (a), above;
(2) Of a kind commonly employed in the performance of those activities naturally and properly incident to the operation of an educational institution such as the owner; and
(3) Wholly and exclusively used for educational purposes by the owner or occupied gratuitously by another nonprofit educational institution (as defined herein) and wholly and exclusively used by the occupant for nonprofit educational purposes. [Emphasis added.]
§ 105-278.6. Real and personal property used for charitable purposes, —(a) Real and personal property owned by:
* * *
(7) A nonprofit, life-saving, first aid, or rescue squad organization;
* * *
shall be exempted from taxation if: (i) As to real property, it is actually and exclusively occupied and used, and as to personal property, it is entirely and completely used, by the owner for charitable purposes-, and (ii) the owner is not organized or operated for profit. [Emphasis added.]
 The focal point in interpreting three of these exemptive statutes is whether the Foundation exclusively used the property for one of the exempted purposes. The Foundation stressfully contends that its use of the property brings it within the excluding *337language of the statute and argues that where the property is used for educational purposes, the general rule requiring a statute to be construed strictly must yield to a less narrow and stringent construction. The Foundation apparently relies upon the following language from Seminary, Inc. v. Wake County, 251 N.C. 775, 112 S.E. 2d 528 (1960):
By the rule of strict construction, however, is not meant that the statute shall be stintingly or even narrowly construed * * * but it means that everything shall be excluded from its operation which does not clearly come within the scope of the language used. . . .
However, the Foundation can find little comfort in this statement. In our opinion, this language does not appear to be inconsistent with the Court’s flat statement that statutes exempting property from taxation because of the purposes for which property is held and used are construed against exemption and in favor of taxation. We note that Seminary also stands for the well-recognized rule that the words used in a statute must be given their natural or ordinary meaning.
Webster’s Third New International Dictionary lists the words “sole” and “single” as synonymous for the word “exclusive.” We also find the following in Ballentine’s Law Dictionary, Second Edition:
exclusive. The Century Dictionary defines the word as meaning, “appertaining to the subject alone; not including, admitting, or pertaining to any other or others; undivided; sole; as, an exclusive right or privilege; exclusive jurisdiction.”
The Foundation nevertheless contends that the term “exclusively” is not to be construed literally and that in the statutes here considered the word refers to the primary and inherent activity and does not preclude incidental activities related to the primarily exempt activity. In support of this position, the Foundation relies upon the case of Rockingham County v. Elon College, 219 N.C. 342, 13 S.E. 2d 618 (1941). In that case, Elon College, an educational institution, owned and rented buildings for business purposes to private enterprise and the net profit from these rentals was exclusively used for educational purposes. In affirming *338the decision of the trial court which held that the property was subject to ad valorem taxes, the Court in part stated:
“The power to grant exemptions under authority of the second sentence in Art. V, sec. 5, which may be exercised in whole, or in part, or not at all, as the General Assembly shall elect, is limited to property held for one or more of the purposes therein designated. Southern Assembly v. Palmer, 166 N.C., 75, 82 S.E., 18; United Brethren v. Comrs., 115 N.C., 489, 20 S.E., 626. Property held for any of these purposes is supposed to be withdrawn from the competitive field of commercial activity, and hence it was not thought violative of the rule of equality or uniformity, to permit its exemption from taxation while occupying this favored position. But when it is thrust into the business life of the community, it loses its sheltered place, regardless of the character of the owner, for it is then held for profit or gain. Trustees v. Avery County, 184 N.C., 469, 114 S.E., 696.... It is not the character of the corporation or association owning the property which determines its status as respects the privilege of exemption, but the purpose for which it is held. Grand Lodge, F. A. M. v. Taylor, 146 Ark., 316, 226 S.W., 129. This is the plain meaning and intent of the Constitution. Corp. Com. v. Construction Co., supra.”
* * *
. . . The fact that a commercial enterprise devotes its entire profits to a charitable or other laudable purpose does not change the character of its business nor the purpose for which it is held. It is still a commercial enterprise, and is held as such. . . .
For like holdings, see Odd Fellows v. Swain, 217 N.C. 632, 9 S.E. 2d 365 (1940); Guilford College v. Guilford County, 219 N.C. 347, 13 S.E. 2d 622 (1941); Redevelopment Comm. v. Guilford County, 274 N.C. 585, 164 S.E. 2d 476 (1968).
 On this record, we conclude that the requisite exclusive use has not been shown. Our conclusion is compelled by the Paper Company’s virtually complete operational control of the Forest pursuant to the contract as amended in 1951. With respect to the operation of the Forest, the 1951 contract amendment provided *339that “the final authority for said programs will rest with Paper Company . . . The record indicates that from 1951 to the present time, the Hofmann Forest has been primarily used by the Paper Company as commercial property. While we recognize the Forest’s importance as an educational and scientific resource and the value of research conducted there, we cannot escape the conclusion that the use of the Forest in this regard is incidental to the activities of the Paper Company. This conclusion is supported by the record and by the provision of the amended contract which states that “study groups or students will do nothing whatsoever to interfere with any program undertaken or in progress by Paper Company in or on Hofmann Forest.”
 The Foundation’s arguments for exemption under the statutes cited above fail on other grounds. G.S. 105-275 exempts real property “exclusively held and used by its owner for educational and scientific purposes as a protected natural area.” The statute defines “protected natural area” as “a nature reserve or park in which all types of wild nature, flora and fauna, and biotic communities are preserved for observation and study.” The Hofmann Forest does not come within the statutory definition of a “protected natural area” due to the extensive program of road building, construction of drainage ditches and fire lanes, site preparation, including disking and burning, leasing of hunting rights to local hunting clubs, and the cutting of timber and pulpwood. While such activities may well constitute prudent management techniques, they certainly do not result in the preservation of “all types of wild nature, flora and fauna . . . .”
G.S. 105-278.4 exempts real property which is “wholly and exclusively used for educational purposes by the owner or occupied gratuitously by another nonprofit educational institution . . . and wholly and exclusively used by the occupant for nonprofit educational purposes.” We have already concluded that said property is not “exclusively used” by the Foundation. Neither is it “occupied gratuitously by another nonprofit educational institution . . . and wholly and exclusively used by the occupant [Paper Company] for nonprofit educational purposes.” On the contrary, the Forest is used by the Paper Company, obviously not a nonprofit educational institution, as a commercial enterprise.
*340  G.S. 105-278.6(a)(7) exempts real property owned by “a nonprofit, life-saving, first aid, or rescue squad organization” if the property is “actually and exclusively occupied and used ... by the owner for charitable purposes.” We have concluded that the property in question is not “exclusively used” by the Foundation. Furthermore, we disagree with the Foundation’s contention that, due to the placement of commas, any nonprofit organization comes within the purview of this statute. Applying the rule of ejusdem generis, it is apparent that “nonprofit” is limited to “lifesaving, first aid, or rescue squad organizations.” Had the Legislature intended such a broad exemption so as to include all nonprofit organizations, it would have so stated without beclouding its intention by the use of the specific type organization set out in G.S. 105-278.6(a)(7).
 Finally, the Foundation contends that the Hofmann Forest is exempt under G.S. 116-16, which provides:
The lands and other property belonging to the University of North Carolina shall be exempt from all kinds of public taxation.
We note that the Foundation is the sole owner of the Forest. Examination of this record discloses that the University of North Carolina has no legal or equitable title to the land in question. Thus, the land simply does not “belong” to the University of North Carolina.
We hold that the Court of Appeals correctly decided that the Foundation did not use the Forest exclusively for an exempt purpose and is not entitled to the exemption applicable to lands “belonging to the University of North Carolina.”
The Foundation next contends that Onslow County, through procedural default, is precluded from collecting ad valorem taxes for 1974 and 1975. This question does not involve Jones County.
From 1969 to 1973, the Foundation paid 10 cents per acre pursuant to G.S. 105-279, in lieu of county taxes which would otherwise be assessed against the Forest. This option was not available in 1974 or 1975 as it was deleted when the statute was amended effective 1 July 1973.
*341On 15 July 1974, the Foundation received a tax notice from Onslow County showing an ad valorem tax liability of $25,466.40 for 1974.
By letter dated 11 November 1974, the Foundation notified the Onslow County Board of Commissioners that it objected to the Forest being subjected to taxation and sought to present its exemption claim to the Board. The Onslow County Manager informed the Foundation in a letter dated 13 January 1975 that the County Commissioners had rejected the Foundation’s letter of 11 November 1974 but would be willing to meet with the Foundation to consider any presentation it wished to make.
The Foundation wrote the County Manager on 29 January 1975 to inform him that it would file a formal application for exemption of Hofmann Forest for 1975. The Foundation requested that any meeting with the Commissioners concerning the 1974 tax liability be deferred until action had been taken on the 1975 application for exemption. The Foundation’s application for exemption was sent by certified mail on 30 January 1975 to the office of the Onslow County Tax Supervisor. This application was received and signed for, apparently by someone in the Tax Supervisor’s office, but the Tax Supervisor testified that he never saw the application.
On 1 August 1975, Onslow County sent the Foundation a tax notice showing a total 1975 ad valorem tax liability of $23,558.98 for the Onslow portion of Hofmann Forest. The Foundation never received acknowledgment of its application for exemption.
On 4 December 1975, pursuant to an application filed by the Foundation, the Property Tax Commission conducted a full de novo hearing into Onslow County’s assessment of Hofmann Forest for 1974 and 1975 ad valorem taxes. The Commission affirmed these assessments.
Upon appeal by the Foundation, the decision of the Commission was affirmed by the superior court which in turn was affirmed by the Court of Appeals.
 The Foundation argues that the 1974 tax assessment was improper due to Onslow County’s failure to give the Foundation notice of the discovery and listing of the property as required by G.S. 105-312(d). We do not agree.
*342From 1969 to 1973, the Hofmann Forest property had been subject to payment of 10 cents per acre, pursuant to G.S. 105-279, in lieu of county taxes otherwise assessed, which payments had in fact been made. These payments in lieu of ad valorem taxes, necessitated by the Attorney General’s opinion in 1969 that the property was no longer exempt, lead us to the conclusion that the property was neither exempt from taxation under G.S. 105-278 nor excluded from the tax base by G.S. 105-275. Furthermore, during the time the Foundation made these payments, it did not contend that the property was either exempt or excluded from the tax base. Thus, the property should have been listed as required by G.S. 105-285.
Upon failure of the Foundation to list this property, it became incumbent upon Onslow County tax officials to discover and list the property pursuant to G.S. 105-312 and G.S. 105-303(b). It appears from the Onslow County tax records, which properly set forth the name and address of the Foundation, the acreage in Onslow County and the payments made thereon pursuant to G.S. 105-279, that the property was, in fact, listed. The Onslow County Tax Supervisor testified that he listed the property in 1974 as the Foundation no longer had the option of paying 10 cents per acre in lieu of taxes. The Tax Supervisor also testified that he did not give the Foundation any notice that the property was being listed. Thus, he did not comply with the discovery procedures of G.S. 105-312(d) which require that notice be sent to the taxpayer.
On the facts here presented, the Tax Supervisor’s failure to send the Foundation the required notice is not fatal to the 1974 tax assessment. The purpose of the notice requirement is to inform the taxpayer that his property is subject to ad valorem taxation. When, in 1969, the Foundation began making payments in lieu of paying the “county taxes otherwise assessed . . .” pursuant to G.S. 105-279, it was, or should have been, aware that its property was included in the tax base. Otherwise, it would not have been required to make these payments as there would have been no “county taxes otherwise assessed . . . .” As everyone is presumed to know the law, the Foundation was charged with the knowledge that the option of making payments in lieu of taxes was not available in 1974. Pinkham v. Mercer, 227 N.C. 72, 40 S.E. 2d 690 (1946). Thus, the Foundation should have known that its property was subject to ad valorem taxation.
*343Although failure to timely notify the Foundation that its property had been discovered delayed its opportunity for a hearing on the matter, this delay did not adversely affect the Foundation’s rights. The Foundation was given a full de novo hearing before the Property Tax Commission which decided the exemption issue adversely to the Foundation. Thus, although the Tax Supervisor was derelict in not giving the Foundation notice of the tax listing as required by G.S. 105-312, we are of the opinion that this omission did not amount to a denial of due process.
In the Jones County case, the Foundation challenged the county’s valuation of the Forest for ad valorem tax purposes.
The Foundation’s appraisal expert testified that for the 31,648 acres in Jones County, the average value per acre was approximately $50. Moreover, he was of the opinion that this valuation should be discounted by about 25 percent due to the Hoerner-Waldorf lease which would influence the price a willing buyer would pay for the property. Thus, he felt that the proper valuation of the property would be between $30 and $36 per acre.
The Jones County Tax Supervisor and Jones County’s regular appraiser both valued the land at $100 per acre. This valuation was adopted by the Tax Commission.
 The lowest rate on the Jones County schedule was $60 per acre, which is higher than the average unadjusted value per acre arrived at by the Foundation’s appraiser. As ad valorem tax assessments are presumed to be correct, the burden of proof is on the taxpayer to show that the assessment was erroneous. In re Appeal of Amp, Inc., 287 N.C. 547, 215 S.E. 2d 752 (1975). In order for the taxpayer to rebut this presumption, he must produce competent, material and substantial evidence that the county tax supervisor used an arbitrary or illegal method of valuation and that the assessment substantially exceeded the true value in money of the property. In re Appeal of Amp, Inc., supra.
 The record indicates that the county’s appraisers divided the property into four classifications, based on soil type, location, and ability of the land to produce, and assigned a different value to each classification. The method used by the county’s appraisers was consistent with the presumption that ad valorem assessments are correct. The Foundation has failed to present material and *344substantial evidence that the method used was arbitrary or illegal.
In its brief filed in this Court, the Foundation contends that the Court of Appeals misconstrued the effect given by the Foundation to Hoerner-Waldorf’s leasehold estate. The Court of Appeals apparently thought that the Foundation’s contention was that the value of the lease should be excluded from the assessment of ad valorem taxes. The Court of Appeals correctly decided that such exclusion would be erroneous. By way of clarification, the Foundation informs us that, in its appraisal of the property, the leasehold estate was considered solely as an encumbrance on the property which would be considered by a willing buyer as affecting the fair market value of the property. It appears then that the Foundation’s position, simply stated, is that its valuation of the property, rather than the County’s valuation, should have been adopted by the Tax Commission. The Commission is free, however, after considering the evidence and weighing the pertinent factors, to adopt the assessment it deems to be proper. Where, as here, the findings of the Tax Commission are supported by competent, material and substantial evidence, they are binding on appeal. In re Appeal of Amp, Inc., supra.
For the reasons stated herein, the decisions of the Court of Appeals are affirmed.
Justice BROCK took no part in the consideration or decision of this case.