Document:

THIS  OPTION  AND  THE  LIMITED  LIABILITY  COMPANY  INTERESTS  PURCHASABLE UPON
EXERCISE  HEREOF  HAVE  NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS
AMENDED,  OR  UNDER  ANY STATE SECURITIES LAWS.  IT MAY NOT BE SOLD, OFFERED FOR
SALE,  PLEDGED  OR  HYPOTHECATED  IN  THE  ABSENCE  OF AN EFFECTIVE REGISTRATION
STATEMENT  AS  TO  THE  SECURITIES  UNDER  SAID  ACT  OR  AN  OPINION OF COUNSEL
SATISFACTORY  TO  THE  COMPANY  THAT  SUCH  REGISTRATION  IS  NOT  REQUIRED.

                              UNIT PURCHASE OPTION

                            Void after July 10, 2006

Option  No.  2                                                  July  10,  2003

     FOR  VALUE  RECEIVED,  the undersigned, PENN OCTANE CORPORATION, a Delaware
corporation  ("Penn  Octane"),  hereby  certifies  that  Jerome  B. Richter (the
"Holder"),  or  assigns,  is  entitled, subject to the terms set forth below, to
purchase  from  Penn Octane after the date (the "Distribution Date") Penn Octane
completes  the  distribution  (the "Distribution") to its stockholders of all of
the  outstanding  common  units  of  Rio  Vista Energy Partners L.P., a Delaware
limited  partnership  ("Rio Vista"), and before 5:00 P.M. New York time, on July
10, 2006 (the "Expiration Date") 25% of the outstanding Units (as defined below)
of Rio Vista GP LLC, a Delaware limited liability company (the "Company"), for a
purchase  price  per Unit (the "Exercise Price") equal to the number of Units to
be  purchased  divided  by  the pro rata portion of the tax basis capital of Rio
Vista  immediately  following  the  Distribution.

     As  used herein the following terms, unless the context otherwise requires,
have  the  following  respective  meanings:

     (a)  The  term  "Company" includes any corporation that shall succeed to or
assume  the  obligations  of  the  Company.

     (b)  The term "Exercise Price" shall have the meaning ascribed to such term
in  the  first  paragraph  hereof.

     (c)  The  term "Limited Liability Company Agreement" shall mean the Amended
and  Restated Limited Liability Company Agreement of the Company dated September
8,  2004.

     (c) The term "Purchase Price" shall mean the amount equal to the product of
the  Exercise  Price  and  the  number  of  Units  to be purchased upon the full
exercise  of  this  Option.

     (d)  The  term  "Units" shall have the meaning ascribed to such term in the
Limited  Liability  Company  Agreement.

     1.  Exercise  of Option. This Option may be exercised in full by the Holder
         -------------------
hereof at any time after the Distribution Date and before the Expiration Date by
surrender  of  this Option, with the form of subscription, addendum agreement to
the  limited liability company agreement of the Company and the Voting Agreement
attached  hereto duly executed by such Holder, to the Company and Penn Octane at
their  respective  principal  offices,  accompanied  by  payment  of  the

<PAGE>
Purchase Price. The Purchase Price shall be paid by cash or check payable to the
order  of  Penn  Octane  Corporation.

     2.  When Exercise Effective. The exercise of this Option shall be deemed to
         -----------------------
have  been  effected  immediately prior to the close of business on the business
day  on  which  this  Option  is  surrendered  as  provided in Section 1 and the
documents referenced in Section 1 are duly executed and delivered as provided in
Section  1,  and at such time the Holder shall be deemed to be the record holder
of  such  Units  for  all  purposes.

     3.  Delivery on Exercise. As soon as practicable after the exercise of this
         --------------------
Option  in full, and in any event within ten (10) business days thereafter, Penn
Octane  at  its  expense  (including  the  payment by it of any applicable issue
taxes)  will  cause  to  be  delivered  to  the  holder  hereof a certificate or
certificates  for  the number of Units to which such holder shall be entitled on
such  exercise.

     4.  Investment  Intent.  Unless  a current registration statement under the
        ------------------
Securities  Act  of  1933, as amended (the "Securities Act"), shall be in effect
with respect to the securities to be purchased upon exercise of this Option, the
Holder  hereof, by accepting this Option, covenants and agrees that, at the time
of  exercise  hereof,  and  at  the  time of any proposed transfer of securities
acquired  upon exercise hereof, such Holder will deliver to the Company and Penn
Octane  a  written  statement that the securities acquired by the Holder are for
such  Holder's  own account, and are not acquired with a view to, or for sale in
connection  with,  any  distribution  thereof  (or  any  portion thereof) except
pursuant  to  current  registration  statement  under  the  Securities Act or an
available  exemption  from  registration.

     5.  Transfer.  This  Option  is  not transferable without the prior written
         --------
consent  of  Penn  Octane.

     6.  No  Rights  or  Liability as a Member. This Option does not entitle the
         -------------------------------------
Holder  hereof  to  any voting rights or other rights as a Member (as defined in
Limited  Liability  Company  Agreement). No provisions hereof and no enumeration
herein  of  the rights or privileges of the Holder hereof shall give rise to any
liability  of  such holder as a Member of the Company. The Units to be purchased
pursuant  to  this  Option  are  subject  to  the terms of the Limited Liability
Company  Agreement.  The Holder shall not be deemed to be a Member and shall not
have  any rights of a Member or rights of an assignee from a Member with respect
to,  any  Units subject to this Option unless and until the Holder has satisfied
all  requirements  for  exercise  of  this  Option pursuant to its terms. Before
receiving  the  Units  subject to this Option, the Holder shall take such action
and  execute such documents as the Company and Penn Octane may require to become
a  Member  of  the  Company.

     7.  Damages.  Penn Octane recognizes and agrees that the Holder hereof will
         ------
not  have  an  adequate  remedy if Penn Octane fails to comply with the terms of
this  Option and that damages will not be readily ascertainable, and Penn Octane
expressly  agrees  that,  in  the  event of such failure, it shall not oppose an
application  by  the  Holder  of this Option or any other person entitled to the
benefits of this Option requiring specific performance of any and all provisions
hereof or enjoining the Penn Octane from continuing to commit any such breach of
the  terms  hereof.

                                        2
<PAGE>
     8.  Notices.  All  notices  and  other communications required or permitted
         -------
hereunder shall be in writing and sent (a) by telecopy if the sender on the same
day  sends  a  confirming copy of such notice by a recognized overnight delivery
service  (charges  prepaid),  or (b) by first class mail, or (c) by a recognized
overnight  delivery  service  (with  charges  prepaid),  addressed (1) if to the
Holder  of this Option, at such Holder's address as it appears in the records of
Penn  Octane (unless otherwise indicated by such Holder), (2) if to Penn Octane,
at  its  office  at  77-530  Enfield  Lane,  Building  D, Palm Desert, CA 92211,
Attention:  Chief  Executive  Officer,  or  at such other address as Penn Octane
shall  have  furnished  to  the Holder of the Option in writing or (3) if to the
Company,  at its office at 820 Gessner Road, Suite 1285, Houston, Texas 77024 or
at  such other address as the Company or Penn Octane shall have furnished to the
Holder  of  the  Option  in  writing.

     9.  Payment  of  Taxes.  Penn Octane shall pay all transfer taxes and other
         ------------------
governmental  charges (not including state and federal income taxes) that may be
imposed  in  respect  to  the  issue or delivery of the Units purchased upon the
exercise  of  this  Option. At the time this Option is exercised, in whole or in
part,  or  at  any  time  thereafter  as requested by Penn Octane, Holder hereby
authorizes withholding from payroll and any other amounts payable to Holder, and
otherwise  agrees  to  make adequate provision for, any sums required to satisfy
the federal, state, local and foreign tax withholding obligations of Penn Octane
or an affiliate, if any, which arise in connection with this Option. This Option
is  not exercisable unless the tax withholding obligations of Penn Octane and/or
any  affiliate  are  satisfied.  Accordingly, Holder may not be able to exercise
this  Option  when  desired  even  though this Option is vested, and Penn Octane
shall  have  no obligation to issue a certificate for such Units or release such
Units  from  any  escrow  provided  for  herein.

     10.  Governing  Law.  All issues and questions concerning the construction,
          --------------
validity,  enforcement  and  interpretation  of  this Option and the attachments
hereto  shall  be governed by, and construed in accordance with, the laws of the
State  of  Texas  without  giving effect to any choice of law or conflict of law
rules  or  provisions  (whether of the State of Texas or any other jurisdiction)
that  would cause the application of the laws of any jurisdiction other than the
State  of  Texas. In furtherance of the foregoing, the internal law of the State
of  Texas  shall control the interpretation and construction of this Option (and
all  attachments hereto), even though under that jurisdiction's choice of law or
conflict  of  law analysis, the substantive law of some other jurisdiction would
ordinarily  apply.

     11.  Consent  to  Jurisdiction.
          -------------------------

          (a)  Each of the parties hereto hereby irrevocably and unconditionally
submits, for itself and its property, to the exclusive jurisdiction of any Texas
state  court or federal court o the United States of America sitting in Houston,
Texas,  and  any  appellate  court from any thereof, in any action or proceeding
arising  out  of  or relating to this Agreement or the transactions contemplated
hereby  or  for recognition or enforcement of any judgment relating thereto, and
each  of  the  parties hereto hereby irrevocably and unconditionally agrees that
all  claims  in  respect  of  any  such  action  or  proceeding may be heard and
determined in such Texas state court or, to the extent permitted by law, in such
federal  court.  Each  of the parties hereto agrees that a final judgment in any
such  action  or  proceeding  shall  be  conclusive and may be enforced in other
jurisdictions  by  suit  on the judgment or in any other manner provided by law.

                                        3
<PAGE>
          (b)  Each of the parties hereto hereby irrevocably and unconditionally
waives,  to  the  fullest  extent  it  may  legally  and  effectively do so, any
objection which it may now or hereafter have to the laying of venue of any suit,
action  or  proceeding  arising  out  of  or  relating  to  this  Option  or the
transactions  contemplated  hereby  in any Texas state or federal court. Each of
the parties hereto hereby irrevocably waives, to the fullest extent permitted by
law,  the  defense of an inconvenient forum to the maintenance of such action or
proceeding  in  any  such  court.

          (c)  Each  party  to  this  Option  irrevocably consents to service of
process  in the manner provided for notices in Section 8. Nothing in this Option
will  affect the right of any party to this Option to serve process in any other
manner  permitted  by  law.

     12.  Waiver  of  Jury  Trial.

          (a)  EACH PARTY ACKNOWLEDGES AND AGREES THAT ANY CONTROVERSY WHICH MAY
ARISE  UNDER  THIS OPTION IS LIKELY TO INVOLVE COMPLICATED AND DIFFICULT ISSUES,
AND  THEREFORE IT HEREBY IRREVOCABLY AND UNCONDITIONALLY WAIVES ANY RIGHT IT MAY
HAVE  TO  A  TRIAL  BY  JURY IN RESPECT OF ANY LITIGATION DIRECTLY OR INDIRECTLY
ARISING  OUT  OF  OR  RELATING  TO  THIS OPTION OR THE TRANSACTIONS CONTEMPLATED
HEREBY  OR  THEREBY.

          (b)  EACH PARTY CERTIFIES AND ACKNOWLEDGES THAT (i) NO REPRESENTATIVE,
AGENT  OR  ATTORNEY  OF ANY OTHER PARTY HAS REPRESENTED, EXPRESSLY OR OTHERWISE,
THAT SUCH OTHER PARTY WOULD NOT, IN THE EVENT OF LITIGATION, SEEK TO ENFORCE THE
FOREGOING  WAIVER,  (ii)  IT  UNDERSTANDS AND HAS CONSIDERED THE IMPLICATIONS OF
SUCH  WAIVER,  (iii)  IT  MAKES  SUCH  WAIVER  VOLUNTARILY, AND (iv) IT HAS BEEN
INDUCED  TO ENTER INTO THIS OPTION BY, AMONG OTHER THINGS, THE MUTUAL WAIVER AND
CERTIFICATIONS  IN  THIS  SECTION  12.

     13.  Miscellaneous. This Option and any term hereof may be changed, waived,
          -------------
discharged  or  terminated  only by an instrument in writing signed by the party
against  which  enforcement  of such change, waiver, discharge or termination is
sought.  The  headings  in  this  Option are for purposes of reference only, and
shall  not  limit  or  otherwise  affect  any  of  the  terms  hereof.

                                          PENN OCTANE CORPORATION

                                          By: /s/ Richard Shore, Jr.
                                              ----------------------------------
                                              Richard Shore, Jr., President

                                        4
<PAGE>
                                          ACKNOWLEDGED AND AGREED TO
                                          WITH RESPECT TO ITS RIGHTS AND
                                          OBLIGATIONS HEREUNDER:

                                          /s/Jerome  B.  Richter
                                          --------------------------------------
                                          Jerome  B.  Richter

                                        5
<PAGE>
                             ATTACHMENT A TO OPTION

                              FORM OF SUBSCRIPTION

                    (TO BE SIGNED ONLY ON EXERCISE OF OPTION)

     To:  PENN  OCTANE  CORPORATION

     The undersigned, the holder of the within Option, hereby irrevocably elects
to  exercise the purchase rights represented by such Option for, and to purchase
thereunder,  25% of the outstanding Units of RIO VISTA GP LLC and herewith makes
payment  of  $___________  therefor,

     and requests that the certificates for such units be issued in the name of,
and  delivered  to  the  undersigned,  whose  address  is ______________________
________________________________________________.

                                         _______________________________________
                                         (Signature  must  conform  in all
                                         respects to name of holder as specified
                                         on the face  of  the  Option)

                                         _______________________________________

                                         _______________________________________
                                         Address

     Dated: ________________________

                                        6
<PAGE>
                             ATTACHMENT B TO OPTION

              ADDENDUM AGREEMENT TO THE LIMITED LIABILITY COMPANY
                          AGREEMENT OF RIO VISTA GP LLC

                                        7
<PAGE>
                             ATTACHMENT C TO OPTION

                                VOTING AGREEMENT

                                        8
<PAGE>RIO VISTA ENERGY PARTNERS L.P.
                              UNIT OPTION AGREEMENT

                            Void after July 10, 2006

Option  No.  1                                      Date of Grant: July 10, 2003
             -

     FOR  VALUE  RECEIVED  and pursuant to the terms of a letter agreement dated
November  29,  2002,  between  Shore  Capital LLC and Penn Octane Corporation, a
Delaware corporation ("Penn Octane"), and a resulting employment agreement dated
                       -----------
May  13,  2003, between Penn Octane and Richard Shore, Jr., the undersigned, RIO
VISTA  ENERGY  PARTNERS L.P., a limited partnership organized and existing under
the  laws  of  the State of Delaware, hereby certifies that Shore Capital LLC is
entitled, subject to the terms set forth below, to purchase from the Partnership
after  the  completion of the distribution by Penn Octane to its stockholders of
all  of the outstanding Common Units of the Partnership and before 5:00 P.M. New
York  time, on July 10, 2006 (the "Expiration Date"), 97,415 Common Units of the
                                   ---------------
Partnership.  The  purchase  price per Common Unit shall be $8.47 (the "Exercise
                                                                        --------
Price").
-----

     The  details  of  this  Option Agreement (this "Agreement") are as follows:
                                                     ---------

     1.  DEFINITIONS.

          (a)  "AFFILIATE"  means,  with  respect  to  any specified person, any
                ---------
person  that  directly  or  through  one  or  more intermediaries controls or is
controlled  by  or is under common control with the specified person. As used in
this  definition,  the  term  "control"  means  the  possession,  directly  or
indirectly,  of the power to direct or cause the direction of the management and
policies  of  a  person,  whether  through  ownership  of  voting securities, by
contract or otherwise. For purposes of clarification, Penn Octane Corporation is
an  Affiliate  of  the  Partnership  and  the  General  Partner.

          (b)  "CODE"  means  the  Internal  Revenue  Code  of 1986, as amended.
                ----

          (c)  "GENERAL  PARTNER"  means  Rio  Vista  GP LLC, a Delaware limited
                ----------------
liability  company,  and  its  successors  or  assigns.

          (d)  "MANAGER"  means  a  manager  of  the  General  Partner under the
                -------
Delaware  Limited  Liability  Company  Act.

          (e) "OFFICER" means any person designated by the General Partner as an
               -------
officer.

          (f)  "OPTION" means an option to acquire Common Units granted pursuant
                ------
to  this  Agreement.

          (g)  "OPTIONHOLDER"  means  the  person  to  whom an Option to acquire
                ------------
Common  Units  is  granted  pursuant  to  this  Agreement.

<PAGE>
          (h)  "PARTNERSHIP"  means  Rio  Vista Energy Partners L.P., a Delaware
                ----------
limited  partnership,  and  its  successors  or  assigns.

          (i) "PARTNERSHIP AGREEMENT" means the limited partnership agreement of
               ----------------------
the  Partnership,  as  amended.

          (j)  "PURCHASE  PRICE"  means  the  amount equal to the product of the
                ---------------
Exercise  Price  and the number of Common Units to be purchased upon exercise of
this  Option.

          (k)  "COMMON  UNIT"  has  the  meaning  set  forth  in the Partnership
                ------------
Agreement  or  any  equity  interest  into  which  a Common Unit is exchanged or
converted.

     2.  ADMINISTRATION.

          (a)  ADMINISTRATION  BY  GENERAL  PARTNER.  The  General Partner shall
administer  this  Agreement. Any interpretation of this Agreement by the General
Partner  and  any  decision by the General Partner under this Agreement shall be
final  and  binding  on  all  persons.

          (b)  POWERS  OF  GENERAL  PARTNER.  The General Partner shall have the
power, subject to, and within the limitations of, the express provisions of this
Agreement:

               (i)  to  construe and interpret this Agreement, and to establish,
amend  and  revoke  rules  and  regulations  for its administration; the General
Partner,  in  the  exercise  of  this power, may correct any defect, omission or
inconsistency  in  this  Agreement,  in a manner and to the extent it shall deem
necessary  or  expedient  to  make  this  Agreement  fully  effective;  and

               (ii)  generally, to exercise such powers and to perform such acts
as  the  General  Partner  deems  necessary  or  expedient  to  promote the best
interests  of  the  Partnership which are not in conflict with the provisions of
this  Agreement.

     3.  NUMBER  OF COMMON UNITS, EXERCISE PRICE AND CAPITALIZATION ADJUSTMENTS.
The  number  of  Common  Units subject to this Option and the exercise price per
Common  Unit  may  be  adjusted from time to time for capitalization adjustments
described  in this Section. If any change is made in the Common Units subject to
this Agreement, without the receipt of consideration by the Partnership (through
conversion,  merger,  consolidation,  reorganization,  recapitalization,  unit
distribution,  distribution  in  property  other  than cash, Common Units split,
liquidating distribution, combination of Common Units, exchange of Common Units,
change  in  structure  or  other  transaction  not  involving  the  receipt  of
consideration  by  the  Partnership), the Common Units subject to this Agreement
will  be  appropriately  adjusted  in the class(es) and number of securities and
price  per Common Unit. The General Partner, the determination of which shall be
final,  binding  and conclusive, shall make such adjustments. (The conversion of
any  convertible  securities  of  the  Partnership  shall  not  be  treated as a
transaction  "without  receipt  of  consideration"  by  the  Partnership.)

     4.  METHOD  OF  PAYMENT.  Payment of the Purchase Price is due in full upon
exercise  of  all or any part of this Option. The Optionholder may elect to make
payment  of  the  Purchase  Price  in  cash  or  by  check.

                                      -2-
<PAGE>
     5.  WHOLE  COMMON UNITS. This Option may only be exercised for whole Common
Units.

     6.  SECURITIES  LAW  COMPLIANCE.  Notwithstanding  anything to the contrary
contained  herein,  this  Option  may  not  be exercised unless the Common Units
issuable  upon  exercise of this Option are then registered under the Securities
Act  or,  if  such  Common Units are not then so registered, the Partnership has
determined that such exercise and issuance would be exempt from the registration
requirements  of  the Securities Act. The Partnership shall use its commercially
reasonable  efforts  to  register  such  Common  Units under the Securities Act.

     7.  TERM.  The  term  of  this  Option  commences  on  the date Penn Octane
completes  the  distribution  to  its stockholders of all the outstanding Common
Units  of  the  Partnership  and  expires  on  the  Expiration  Date.

     8.  EXERCISE.

          (a) Subject to Section 8(c), the Optionholder may exercise this Option
                         ------------
during  its term by delivering a Notice of Exercise (in a form designated by the
General  Partner)  together  with  the  Purchase  Price  to the Secretary of the
General  Partner,  or to such other person as the General Partner may designate,
during  regular  business  hours, together with such additional documents as the
General  Partner  may  then  require.

          (b)  By  exercising  this  Option,  the Optionholder agrees that, as a
condition to any exercise of this Option, the Partnership or the General Partner
may  require  the Optionholder to enter an arrangement providing for the payment
by  the Optionholder to the Partnership of any tax withholding obligation of the
Partnership,  as  reasonably determined by the Partnership, arising by reason of
(1) the exercise of this Option, or (2) the disposition of Common Units acquired
upon  such  exercise.

          (c)  Notwithstanding  anything herein to the contrary, during the term
of this Option, this Option may only be exercised during the first ten (10) days
of  the  first  month  of each fiscal quarter of the Partnership and during such
other  periods  as  the General Partner may designate in its sole discretion for
purposes  of  minimizing  the accounting costs to the Partnership resulting from
such  exercise.

     9.  TRANSFERABILITY.  This  Option  is  not  transferable,  except  to  any
Affiliate  of  the  Optionholder, and is exercisable only by the Optionholder or
such  Affiliate. The transferability of the Common Units issued upon exercise of
this Option shall be subject to the conditions, restrictions and limitations set
forth  in this Agreement, the Partnership Agreement and any other agreements the
Optionholder  may  have  with  the  Partnership.

          (a) The provisions of this Section 9 may be waived with respect to any
                                     ---------
transfer by the Partnership, upon duly authorized action of the General Partner.

          (b) Any sale or transfer, or purported sale or transfer, of the Common
Units  by  the Optionholder shall be null and void unless the terms, conditions,
and  provisions  of  this  Section  9  are  observed  and  followed.
                           ----------

                                      -3-
<PAGE>
     10.  WITHHOLDING  OBLIGATIONS

          (a)  At  the time this Option is exercised, in whole or in part, or at
any  time  thereafter  as  requested  by  the  Partnership, you hereby authorize
withholding  from  payroll  and  any other amounts payable to you, and otherwise
agree  to make adequate provision for, any sums required to satisfy the federal,
state,  local  and  foreign tax withholding obligations of the Partnership or an
Affiliate,  if  any,  which  arise  in  connection  with  this  Option.

          (b)  This  Option  is  not  exercisable  unless  the  tax  withholding
obligations  of the Partnership and/or any Affiliate are satisfied. Accordingly,
you may not be able to exercise this Option when desired even though this Option
is  vested,  and the Partnership shall have no obligation to issue a certificate
for  such Common Units or release such Common Units from any escrow provided for
herein.

     11.  TAX  CONSEQUENCES  AND  CAPITAL ACCOUNT UPON EXERCISE OF OPTION. It is
intended  that neither the Optionholder, the Partnership nor any of the partners
(owners)  of the Partnership shall have any federal income tax consequences upon
grant  of  this  Option,  or,  except as described herein, upon exercise of this
Option.  Additionally, it is intended that the Optionholder shall not be treated
as  a  partner  with respect to the Common Units subject to this Agreement until
such  time  as  this  Option is exercised. It is intended that, upon exercise of
this Option, the Optionholder shall include in income ("Exercise Income") in the
tax  year  of exercise an amount equal to the excess, if any, of the fair market
value  of  Common  Units  on the date of exercise over the sum of the amount the
Optionholder  has  paid  or will pay to the Partnership ("Option Consideration")
upon  the  grant and exercise of the Option. It is intended that the Partnership
shall  be entitled to a deduction equal to the amount of Exercise Income, which,
if  the  Partnership  continues  to  be  a  partnership  for  federal income tax
purposes,  shall  be  allocated  solely to the partners of the Partnership other
than the Optionholder to whom the Exercise Income is attributable. Upon exercise
of  this  Option,  Optionholder  shall receive a positive capital account in the
Partnership  (assuming  the  Partnership  continues  to  be  classified  as  a
partnership for federal income purposes) equal to the sum of the Exercise Income
to  the  Optionholder  and  the  amount  of  Option  Consideration  paid  by the
Optionholder.  Should  the  federal  income  tax  consequences  differ from that
described  in  this  section,  the  General  Partner shall have the authority to
change  the  capital  account  or  allocations  of  income  and deduction to the
Optionholder  as described herein in manner which in its discretion most closely
achieves the same economic effect of the consequences described in this Section.
Notwithstanding  anything herein to the contrary, the General Partner shall have
the  authority  to  change the tax reporting described above with respect to the
issuance or exercise of this Option or alter the capital accounts or allocations
of  Partnership  items  as  necessary  to  preserve or achieve the uniformity of
Common  Units.

     12.  NOTICES.  Any  notices  provided  for in this Option or this Agreement
shall be given in writing and shall be deemed effectively given upon receipt or,
in  the  case  of notices delivered by the Partnership to the Optionholder, five
(5)  days after deposit in the United States mail, postage prepaid, addressed to
the  Optionholder  at  the  last  address  provided  to  the  Partnership.

                                      -4-
<PAGE>
     13.  THIS  AGREEMENT;  PARTNERSHIP AGREEMENT. This Option is subject to all
the provisions of this Agreement, the provisions of which are hereby made a part
of this Option, and is further subject to all interpretations, amendments, rules
and  regulations which may from time to time be promulgated and adopted pursuant
to this Agreement, and the Common Units to be delivered are subject to the terms
of  the Partnership Agreement. In the event of any conflict among Optionholder's
rights under the Common Units, this Agreement and the Partnership Agreement, the
terms  of  the  Partnership  Agreement  shall  control.

     14.  MISCELLANEOUS.

          (a)  AVAILABILITY OF COMMON UNITS. During the term of this Option, the
Partnership  shall  keep  available  at  all  times  the  number of Common Units
required  to  satisfy  the  Option.

          (b)  PARTNER  RIGHTS. No Optionholder shall be deemed to be partner of
the  Partnership,  or  to  have  any  of the rights of a partner or rights of an
assignee  from a partner with respect to, any Common Units subject to the Option
unless  and  until such Optionholder has satisfied all requirements for exercise
of  the  Option  pursuant  to  its  terms.

          (c)  INVESTMENT  ASSURANCES.  Unless  the  Common  Units issuable upon
exercise  of  this  Option  are  then  registered  under the Securities Act, the
General  Partner  may  require  an Optionholder, as a condition of exercising or
acquiring  Common  Units under the Option, to give written assurances that he is
an  "accredited  investor,"  as  defined  in the rules and regulations under the
Securities  Act.  The General Partner may, upon advice of counsel to the General
Partner,  place  legends on Common Units certificates issued under the Option as
such  counsel  deems necessary or appropriate in order to comply with applicable
securities laws, including, but not limited to, legends restricting the transfer
of  the  Common  Units.

          (d)  PARTNERSHIP  AGREEMENT.  Before  receiving  Common  Units,  the
Optionholder  shall  take  such action and execute such documents as the General
Partner  may  require  to  become  a  partner  of  the  Partnership.

          IN  WITNESS  WHEREOF,  this Option Agreement has been duly executed by
the parties hereto as of the Date of Grant.

                                     RIO VISTA ENERGY PARTNERS L.P.

                                     By: RIO VISTA GP LLC, general partner

                                         By: /s/ Ian T. Bothwell
                                             -----------------------------------
                                                 Ian T. Bothwell, Treasurer

                                      -5-
<PAGE>
ACCEPTED AND AGREED:

SHORE CAPITAL LLC

By: /s/ Richard Shore, Jr.
   ----------------------------------
        Richard Shore, Jr., President

                                      -6-
<PAGE>

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00074-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00074-of-00352.parquet"}]]