10.27 First Amendment to the First Amended and Restated Agreement of Limited Partnership of Rio Vista Operating Partnership L.P. dated as of October 26, 2005.  (Incorporated by reference to the Company’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2005 filed on November 21, 2005, SEC File No. 000-24394).

10.28 Amended and Restated Promissory Note by Jerome B. Richter to the Company dated November 15, 2005.  (Incorporated by reference to the Company’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2005 filed on November 21, 2005, SEC File No. 000-24394). 

10.29 Agreement dated as of November 15, 2005 by and between Penn Octane Corporation and Jerome B. Richter.  (Incorporated by reference to the Company’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2005 filed on November 21, 2005, SEC File No. 000-24394). 

10.30 Ella-Brownsville Pipeline Lease Agreement effective as of August 1, 2006 between Seadrift Pipeline Corporation and Penn Octane Corporation. (Incorporated by reference to the Company’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2006 filed on August 14, 2006, SEC File No. 000-24394).

10.31 Amendment to Pledge and Security Agreement between the Penn Octane Corporation and Jerome B. Richter dated October 13, 2006.  (Incorporated by reference to the Company’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2006 filed on November 20, 2006, SEC File No. 000-24394).

10.32  First Amendment to Amended and Restated Limited Liability Company Agreement of Rio Vista GP LLC dated October 6, 2006.  (Incorporated by reference to the Company’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2006 filed on November 20, 2006, SEC File No. 000-24394).

10.33  Unit Purchase Option effective February 6, 2007 between Shore Trading LLC and Penn Octane Corporation.  (Incorporated by reference to the Company’s Annual Report on Form 10-K for the year ended December 31, 2006 filed on April 17, 2007, SEC File No. 000-24394).

10.34 Consent to Transfer of Units, Acknowledgement of Representation, and Waiver of Conflicts dated February 6, 2007 among Penn Octane Corporation, Rio Vista GP LLC, and Shore Trading LLC. (Incorporated by reference to the Company’s Annual Report on Form 10-K for the year ended December 31, 2006 filed on April 17, 2007, SEC File No. 000-24394).

10.35  Consulting Agreement entered into March 5, 2007, with an effective date of November 15, 2006 by and between Penn Octane Corporation, and Rio Vista Energy Partners L.P., and JBR Capital Resources, Inc. (Incorporated by reference to the Company’s Annual Report on Form 10-K for the year ended December 31, 2006 filed on April 17, 2007, SEC File No. 000-24394).

10.36  Letter agreement dated March 5, 2007 by and between Penn Octane Corporation, Rio Vista Energy Partners L.P. and JBR Capital Resources, Inc. (Incorporated by reference to the Company’s Annual Report on Form 10-K for the year ended December 31, 2006 filed on April 17, 2007, SEC File No. 000-24394).

10.37  Amended Form of Common Stock Purchase Warrant under the Penn Octane Corporation 2001 Warrant Plan. (Incorporated by reference to the Company’s Annual Report on Form 10-K for the year ended December 31, 2006 filed on April 17, 2007, SEC File No. 000-24394).

10.38 Form of Penn Octane Corporation Chairman Services Agreement. (Incorporated by reference to the Company’s Annual Report on Form 10-K for the year ended December 31, 2006 filed on April 17, 2007, SEC File No. 000-24394).

10.39 Form of Penn Octane Corporation Director and Officer Indemnification Agreement. (Incorporated by reference to the Company’s Annual Report on Form 10-K for the year ended December 31, 2006 filed on April 17, 2007, SEC File No. 000-24394).

10.40 Form of Penn Octane Corporation Director Services Agreement. (Incorporated by reference to the Company’s Annual Report on Form 10-K for the year ended December 31, 2006 filed on April 17, 2007, SEC File No. 000-24394).

10.41 Form of Rio Vista GP LLC Chairman Services Agreement. (Incorporated by reference to the Company’s Annual Report on Form 10-K for the year ended December 31, 2006 filed on April 17, 2007, SEC File No. 000-24394).

10.42 Form of Rio Vista GP LLC Manager Services Agreement. (Incorporated by reference to the Company’s Annual Report on Form 10-K for the year ended December 31, 2006 filed on April 17, 2007, SEC File No. 000-24394).

10.43  Form of Rio Vista GP LLC Manager and Officer Indemnification Agreement. (Incorporated by reference to the Company’s Annual Report on Form 10-K for the year ended December 31, 2006 filed on April 17, 2007, SEC File No. 000-24394).

10.44Form of Nonqualified Unit Option Agreement under the 2005 Rio Vista Energy Partners L.P. Equity Incentive Plan. (Incorporated by reference to the Company’s Annual Report on Form 10-K for the year ended December 31, 2006 filed on April 17, 2007, SEC File No. 000-24394).

10.45 Amended and Restated Line Letter dated December 7, 2006 between RZB Finance LLC and Penn Octane Corporation. (Incorporated by reference to the Company’s Annual Report on Form 10-K for the year ended December 31, 2006 filed on April 17, 2007, SEC File No. 000-24394).

10.46  Consulting Agreement with An Effective Date Of November 1, 2006 By And Between Penn Octane Corporation And Rio Vista Energy Partners L.P. And Ricardo Rodriguez Canney.  (Incorporated by reference to the Company’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2007 filed on August 20, 2007, SEC File No. 000-24394).

10.47   Consulting Agreement Made And Entered Into As Of The 2nd Day Of July, 2007 Between Rio Vista Energy Partners, L.P. And Ceocast, Inc.  (Incorporated by reference to the Company’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2007 filed on August 20, 2007, SEC File No. 000-24394).

10.48  Employment And Non-Competition Agreement Effective As Of The 27th Day Of July, 2007 Made By And Between Regiona And W. Gary Farrar, III.  (Incorporated by reference to the Company’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2007 filed on August 20, 2007, SEC File No. 000-24394).

10.49               Escrow Agreement Between Rio Vista Energy Partners L.P., Regional Enterprises, Inc., W. Gary Farrar, Jr., A Resident Of The Commonwealth Of Virginia, And First Capital Bank,  Effective As Of The 27th Day Of July, 2007.  (Incorporated by reference to the Company’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2007 filed on August 20, 2007, SEC File No. 000-24394).

10.50  Loan Agreement Dated As Of July 26, 2007, And Entered Into Between Rio Vista Energy Partners L.P. And RZB Finance LLC.  (Incorporated by reference to the Company’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2007 filed on August 20, 2007, SEC File No. 000-24394)

10.51  Guaranty And Agreement Between Regional Enterprises, Inc. And RZB Finance LLC Dated As Of July 26, 2007.  (Incorporated by reference to the Company’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2007 filed on August 20, 2007, SEC File No. 000-24394).

10.52  Guaranty And Agreement Between Penn Octane Corporation and RZB Finance LLC Dated As Of July 26, 2007.  (Incorporated by reference to the Company’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2007 filed on August 20, 2007, SEC File No. 000-24394).

10.53  Guaranty And Agreement Between Rio Vista Operating Partnership L.P. and RZB Finance LLC Dated As Of July 26, 2007.  (Incorporated by reference to the Company’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2007 filed on August 20, 2007, SEC File No. 000-24394).

10.54  $5,000,000 Promissory Note Dated July 26, 2007 Issued By Rio Vista Energy Partners L.P., To RZB Finance LLC.  (Incorporated by reference to the Company’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2007 filed on August 20, 2007, SEC File No. 000-24394).

10.55   General Security Agreement dated July 26, 2007 between RZB Finance LLC and Regional Enterprises, Inc.  (Incorporated by reference to the Company’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2007 filed on August 20, 2007, SEC File No. 000-24394).

10.56               Pledge Agreement, Made This 26th Day Of July, 2007, By And Between: Rio Vista Energy Partners L.P. And RZB Finance LLC.  (Incorporated by reference to the Company’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2007 filed on August 20, 2007, SEC File No. 000-24394).

10.57 First Amendment To Line Letter Dated As Of July 26, 2007, Between RZB Finance LLC And Penn Octane Corporation.  (Incorporated by reference to the Company’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2007 filed on August 20, 2007, SEC File No. 000-24394).

10.58  Debt Assumption Agreement        Made As Of The 26th Day Of July, 2007, By And Between Rio Vista Energy Partners L.P. And Regional Enterprises, Inc., A Virginia Corporation.  (Incorporated by reference to the Company’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2007 filed on August 20, 2007, SEC File No. 000-24394).

10.59 $5,000,000 Debt Assumption Note Dated July 26, 2007 Issued By Regional Enterprises, Inc., To Rio Vista Energy Partners L.P.  (Incorporated by reference to the Company’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2007 filed on August 20, 2007, SEC File No. 000-24394).

10.60  $2,500.000 Promissory Note Dated July 26, 2007 Issued By Regional Enterprises, Inc., To Rio Vista Energy Partners L.P.  (Incorporated by reference to the Company’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2007 filed on August 20, 2007, SEC File No. 000-24394).

10.61 Environmental Indemnity Agreement Made As Of The 26th Day Of July, 2007 By Regional Enterprises, Inc. And RZB Finance LLC.  (Incorporated by reference to the Company’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2007 filed on August 20, 2007, SEC File No. 000-24394).

• Reaffirmation Of Security Agreements, Dated As Of July 26, 2007 By And Among Rio Vista Energy Partners L.P., Penn Octane Corporation And Rio Vista Operating Partnership L.P. And RZB Finance LLC.  (Incorporated by reference to the Company’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2007 filed on August 20, 2007, SEC File No. 000-24394).