SC 13D

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Schedule 13D

Under the Securities Exchange Act of 1934
(Amendment No. )*

ST. LAWRENCE SEAWAY CORPORATION

(Name of Issuer)

Common Stock, $0.01 Par Value
(Title of Class of Securities)

791162100
(CUSIP Number)

Bryan H. Lawrence
Yorktown Energy Partners V, L.P.
410 Park Avenue
19th Floor
New York, New York 10022
(212) 515-2112

Copies to:

Ann Marie Cowdrey
Thompson & Knight LLP
One Arts Plaza
1722 Routh Street, Suite 1500
Dallas, Texas 75201-2533
(214) 969-1700

(Name, Address and Telephone Number of Person
Authorized to Receive Notices and Communications)

February 14, 2011
(Date of Event which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 204.13d-1(g), check the following box.     o

NOTE: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See Rule 13d-7 for other parties to whom copies are to be sent.

*The remainder of the cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

CUSIP No. 791162100 

1	NAMES OF REPORTING PERSONS YORKTOWN ENERGY PARTNERS V, L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)
	(a)   o
	(b)   o
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)
	OO
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e)
	o
6	CITIZENSHIP OR PLACE OF ORGANIZATION
	Delaware
		7	SOLE VOTING POWER
NUMBER OF			17,938,309
SHARES		8	SHARED VOTING POWER
BENEFICIALLY
OWNED BY			0
EACH		9	SOLE DISPOSITIVE POWER
REPORTING
PERSON			17,938,309
WITH		10	SHARED DISPOSITIVE POWER
			0
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	17,938,309 (1)
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)
	o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	37.8%(2)
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
	PN

(1) Yorktown V Company LLC is the sole general partner of Yorktown Energy Partners V, L.P. As a result, Yorktown V Company LLC may be deemed to have the power to vote or direct the vote or to dispose or direct the disposition of the shares owned by Yorktown Energy Partners V, L.P. Yorktown V Company LLC disclaims beneficial ownership of the securities owned by Yorktown Energy Partners V, L.P. in excess of its pecuniary interest therein.

(2) Based on 47,518,739 shares of common stock issued and outstanding after the February 14, 2011 closing of that certain Agreement and Plan of Merger dated January 31, 2011 by and among the St. Lawrence Seaway Corporation, a Delaware corporation, St. Lawrence Merger Sub, Inc., a Delaware corporation, and Nytis Exploration (USA) Inc., a Delaware corporation.

CUSIP No. 791162100 

1	NAMES OF REPORTING PERSONS YORKTOWN V COMPANY LLC
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)
	(a)   o
	(b)   o
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)
	OO
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e)
	o
6	CITIZENSHIP OR PLACE OF ORGANIZATION
	Delaware
		7	SOLE VOTING POWER
NUMBER OF			17,938,309
SHARES		8	SHARED VOTING POWER
BENEFICIALLY
OWNED BY			0
EACH		9	SOLE DISPOSITIVE POWER
REPORTING
PERSON			17,938,309
WITH		10	SHARED DISPOSITIVE POWER
			0
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	17,938,309 (1)
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)
	o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	37.8%(2)
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
	OO

(1) Yorktown V Company LLC is the sole general partner of Yorktown Energy Partners V, L.P. As a result, Yorktown V Company LLC may be deemed to have the power to vote or direct the vote or to dispose or direct the disposition of the shares owned by Yorktown Energy Partners V, L.P. Yorktown V Company LLC disclaims beneficial ownership of the securities owned by Yorktown Energy Partners V, L.P. in excess of its pecuniary interest therein.

(2) Based on 47,518,739 shares of common stock issued and outstanding after the February 14, 2011 closing of that certain Agreement and Plan of Merger dated January 31, 2011 by and among the St. Lawrence Seaway Corporation, a Delaware corporation, St. Lawrence Merger Sub, Inc., a Delaware corporation, and Nytis Exploration (USA) Inc., a Delaware corporation.

Item 1. Security and Issuer.

     This Schedule 13D relates to the common stock, par value $0.01 per share (the “Common Stock”), of St. Lawrence Seaway Corporation, a Delaware corporation (the “Company”), whose principal executive offices are located at 1700 Broadway, Suite 2020, Denver, Colorado 80290.

Item 2. Identity and Background.

     This statement is filed by Yorktown Energy Partners V, L.P., a Delaware limited partnership (“Yorktown”), and Yorktown V Company LLC, a Delaware limited liability company (“Yorktown Company”). The principal office and business address of Yorktown and Yorktown Company is 410 Park Avenue, 19th Floor, New York, New York 10022. The principal business of Yorktown is investing in equity securities of energy companies. The principal business of Yorktown Company is managing Yorktown.

     Neither Yorktown nor Yorktown Company has, during the last five years, been convicted in a criminal proceeding (excluding traffic violations or similar misdemeanors).

     Neither Yorktown nor Yorktown Company has, during the last five years, been a party to a civil proceeding of a judicial or administrative body of competent jurisdiction and as a result of such proceeding was or is subject to a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violation with respect to such laws.

Item 3. Source and Amount of Funds or Other Consideration.

     Yorktown acquired 2,500 shares of common stock, par value $0.01 per share (“Nytis Common Stock”), of Nytis Exploration (USA) Inc., a Delaware corporation (“Nytis USA”) on May 5, 2005 and 8,500 shares of Nytis Common Stock on May 19, 2005, in private placements in exchange for $2.5 million and $8.5 million, respectively, paid from Yorktown’s working capital and partnership funds. On February 14, 2011, Nytis USA completed a reverse merger (the “Merger”) whereby St. Lawrence Merger Sub, Inc., a Delaware corporation and subsidiary of the Company, merged with and into Nytis USA, and the Company issued Yorktown 17,938,309 shares of Common Stock in consideration for Yorktown’s 11,000 shares of common stock of Nytis USA.

Item 4. Purpose of Transaction.

     Yorktown acquired its 17,938,309 shares of Common Stock for investment purposes. As of the date hereof, neither Yorktown nor Yorktown Company has formulated any specific plans or proposals which relate to or would result in: (a) the acquisition by any person of additional securities of the Company or the disposition of securities of the Company; (b) an extraordinary corporate transaction, such as a merger, reorganization or liquidation involving the Company or any of its subsidiaries; (c) a sale or transfer of a material amount of assets of the Company or any of its subsidiaries; (d) any change in the present board of directors or management of the Company, including any plans or proposals to change the number or term of directors or to fill any existing vacancies on the board of the Company; (e) any material change in the present capitalization or dividend policy of the Company; (f) any other material change in the Company’s business or corporate structure; (g) changes in the Company’s charter, bylaws or instruments corresponding thereto or other actions which may impede the acquisition of control of the Company by any person; (h) causing a class of securities of the Company to be delisted from a national securities exchange or to cease to be authorized to be quoted in an inter-dealer quotation system of a registered national securities association; (i) causing a class of equity securities of the Company to become eligible for termination of registration pursuant to Section 12(g)(4) of the Securities Exchange Act of 1934, as amended; or (j) any action similar to any of those enumerated above.

Item 5. Interest in Securities of the Issuer.

(a) As of February 24, 2011, Yorktown and Yorktown Company beneficially owned 17,938,309 shares of Common Stock, representing 38.2% of the Company’s outstanding shares of common stock (based on 47,518,739 shares of common stock issued and outstanding after the closing of the Merger on February 14, 2011).

(b)	Yorktown Company is the sole general partner of Yorktown. Yorktown Company has the sole power to cause Yorktown to vote or direct the vote or to dispose or direct the disposition of the shares owned by Yorktown.
(c)	Except as otherwise described herein, neither Yorktown nor Yorktown Company has effected any transaction in the Common Stock during the past 60 days.
(d)	No person other than Yorktown has the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the shares of Common Stock reported on this Schedule 13D.
(e)	Inapplicable.

Item 6. Contracts, Arrangements, Understandings or Relationships with Respect to Securities of the Issuer.

     None.

Item 7. Material to Be Filed as Exhibits.

Exhibit 1 — Joint Filing Agreement dated February 24, 2011

SIGNATURES

     After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Date: February 24, 2011

YORKTOWN ENERGY PARTNERS V, L.P.
By:	Yorktown V Company LLC, its general partner
	By:	/s/ Robert A. Signorino
		Robert A. Signorino, Member
YORKTOWN V COMPANY LLC
By:	/s/ Robert A. Signorino
	Robert A. Signorino, Member

EX-99.1

EXHIBIT 1

JOINT FILING AGREEMENT

     In accordance with Rule 13d-1(k) promulgated under the Securities Exchange Act of 1934, as amended, the undersigned persons hereby agree to the joint filing on behalf of each of them of a statement on Schedule 13D (including amendments thereto) with respect to the common stock of ST. LAWRENCE SEAWAY CORPORATION and further agree that this Joint Filing Agreement be included as an Exhibit to such joint filing. In evidence thereof each of the undersigned, being duly authorized, hereby execute this Agreement on the date set forth below.

Date: February 24, 2011

YORKTOWN ENERGY PARTNERS V, L.P.
By:	Yorktown V Company LLC, its general partner
	By:	/s/ Robert A. Signorino
		Robert A. Signorino, Member
YORKTOWN V COMPANY LLC
By:	/s/ Robert A. Signorino
	Robert A. Signorino, Member