<PAGE>   1
                                                   EXHIBIT 10A








           THRIFT AND EMPLOYEE STOCK OWNERSHIP PLAN

                              OF

               AMERICAN PETROFINA, INCORPORATED



<PAGE>   2
           THRIFT AND EMPLOYEE STOCK OWNERSHIP PLAN
                              OF
               AMERICAN PETROFINA, INCORPORATED

                       TABLE OF CONTENTS

                                                            Page
                                                            ----
PREAMBLE      ..........................................      1

ARTICLE I     DEFINITIONS AND CONSTRUCTION .............      2
              Section 1.1  Definitions .................      2
              Section 1.2  Participation ...............     11

ARTICLE II    PARTICIPATION ............................     11
              Section 2.1  Participation ...............     11

ARTICLE III   CONTRIBUTIONS AND ALLOCATIONS ............     12
              Section 3.1  Participant Elected
                           Contributions ...............     12
              Section 3.2  Employer Matching
                           Contributions ...............     14
              Section 3.3  Tax Credit
                           Contributions ...............     14
              Section 3.4  Payment to Trustee ..........     14
              Section 3.5  Crediting of Contribu-
                           tions and Forfeitures .......     17

ARTICLE IV    TRUST AND INVESTMENT PROVISIONS ..........     20
              Section 4.1  Trust and Trustee  ..........     20
              Section 4.2  Investment of ESOP and
                           PAYSOP Accounts .............     20
              Section 4.3  Investment of Participant
                           Thrift, Participant
                           Deferred, Company Thrift
                           and Company Matching
                           Accounts ....................     20
              Section 4.4  Purchases of Company and
                           PSA Stock and Government
                           Bonds .......................     21
              Section 4.5  Voting Rights ...............     23

ARTICLE V     VESTING AND DISTRIBUTION EVENTS ..........     24
              Section 5.1  Retirement or Disability ....     24
              Section 5.2  Death .......................     24
              Section 5.3  Break in Service ............     24

ARTICLE VI    DISTRIBUTIONS AND FORFEITURES ............     25
              Section 6.1  Time and Form of
                           Distribution ................     25



                              (i)
<PAGE>   3
                                                            Page
                                                            ----
              Section 6.2  Distribution of Retire-
                           ment, Disability and
                           Death Benefits ..............     26
              Section 6.3  Withdrawals by Vested
                           Participants ................     27
              Section 6.4  Withdrawals by Partially
                           Vested Participants .........     29
              Section 6.5  Withdrawals by Nonvested
                           Participants ................     31
              Section 6.6  Break in Service
                           Distribution ................     32
              Section 6.7  Application of
                           Forfeitures .................     33
              Section 6.8  Distributions to Minors
                           and Persons Under
                           Legal Disability ............     33

ARTICLE VII   PLAN ADMINISTRATION ......................     33
              Section 7.1  Appointment to Committee ....     33
              Section 7.2  Powers and Duties of the
                           Committee ...................     34
              Section 7.3  Rules, Records and Reports ..     35
              Section 7.4  Administration Expenses
                           and Taxes ...................     35
              Section 7.5  Claims Procedure ............     36

ARTICLE VIII  AMENDMENT AND TERMINATION ................     37
              Section 8.1  Amendment ...................     37
              Section 8.2  Termination .................     38

ARTICLE IX    MISCELLANEOUS GENERAL PROVISIONS .........     38
              Section 9.1  Spendthrift Provision .......     38
              Section 9.2  Maximum Annual Additional
                           Limitation ..................     38
              Section 9.3  Limitations on
                           Responsibilities ............     40
              Section 9.4  Committee Indemnification ...     40
              Section 9.5  Employment Noncontractual ...     41
              Section 9.6  Merger or Consolidation .....     41
              Section 9.7  Employee Stock Ownership
                           Plan Merger Into Thrift
                           Plan ........................     41
              Section 9.8  Applicable Law ..............     42



                             (ii)

<PAGE>   4
           THRIFT AND EMPLOYEE STOCK OWNERSHIP PLAN

                              OF

               AMERICAN PETROFINA, INCORPORATED


    THIS THRIFT AND EMPLOYEE STOCK OWNERSHIP PLAN, made and 
executed at Dallas, Texas by the undersigned Employers.

                       WITNESSETH THAT:

    WHEREAS, the Employers have heretofore adopted for the 
benefit of their employees a qualified profit sharing plan 
known as the Thrift Plan for Employees of American Petrofina, 
Incorporated and Certain Subsidiaries (the "Thrift Plan") and a 
qualified tax credit employee stock ownership plan known as the 
Employee Stock Ownership Plan of American Petrofina, 
Incorporated (the "Employee Stock Ownership Plan"); and

    WHEREAS, the Employers now desire to continue said employee 
benefits plans without interruption by consolidating the Thrift 
Plan and the Employee Stock Ownership Plan into a single plan 
providing participating employees with the major benefit 
features of both Plans and adding thereto a cash or deferred 
arrangement qualifying under the provisions of Section 401(k) 
of the Internal Revenue Code:

    NOW, THEREFORE, subject to the provisions of Section 9.7 of 
this Plan and pursuant to the authority reserved to the 
Employers pursuant to Section 16.1 of the Thrift Plan and 
Section 12.1 of the Employee Stock Ownership Plan, the Thrift 
Plan and the Employee Stock Ownership Plan are hereby amended 
<PAGE>   5
and restated in their entirety to merge the Employee Stock 
Ownership Plan into the Thrift Plan which, as so amended and 
restated in its entirety, shall read as follows:

                          ARTICLE I.

                 DEFINITIONS AND CONSTRUCTION

    Section 1.1  Definitions.  Unless the context clearly 
indicates otherwise, when used in this Plan:

           (a)   "Affiliated Company" means (1) any corporation 
    or organization, other than an Employer, which is a member         
    of a controlled group of corporations (within the meaning          
    of Section 414(b) of the Code) or of an affiliated service         
    group (within the meaning of Section 414(m) of the Code)           
    with respect to which an Employer is also a member, (2) any        
    incorporated or unincorporated trade or business which             
    along with an Employer is under common control (within the         
    meaning of the regulations from time to time promulgated by        
    the Secretary of the Treasury pursuant to Section 414(c) of        
    the Code), and (3) any other incorporated or unincorporated        
    trade or business which is designated by the Board of              
    Directors of the Company as an Affiliated Company for the          
    purposes of the Plan; provided, however, that for the              
    purposes of Section 9.2 of the Plan, Section 414(b) and (c)        
    of the Code shall be applied as modified by Section 415(h)         
    of the Code.                                                       





                                     -2-
<PAGE>   6
      (b)   "Basic Compensation" means the base salary and 
wages (determined without regard to any Basic Compensation 
reduction agreement entered into pursuant to Section 3.1) 
regularly payable to a Participant as part of his 
Compensation after becoming a Participant in the Plan but 
shall not include any employee bonus payments, 
straight-time, overtime or premium overtime pay, severance 
pay, callback pay, night-shift differential,  Matching or 
Tax Credit Contributions to this Plan or any prior plan, 
automobile allowance, living allowance, premium paid on any 
life insurance policy or other form of special remuneration.

      (c)   "Break In Service" means any  Service 
Computation Period during which an Employee fails to 
complete more than 500 Hours of Service.

      (d)   "Code"  means  the  Internal Revenue Code of 
1954, as amended from time to time, or any successor  
revenue code which may hereafter be adopted in lieu  
thereof, and references herein to any specific provision of 
the Code shall be deemed also to refer to the corresponding 
provision of the Code as it may hereafter be so amended or 
replaced.

      (e)   "Committee"   means the Committee appointed by 
the Board of directors of the Company to administer the   
Plan on behalf of the Employers.

      (f)   "Company"  means American Petrofina,   
Incorporated.





                                     -3-
<PAGE>   7
      (g)   "Company Matching Account"  means the account 
established and maintained under the Plan by the Committee 
to record a Participant's interest under this Plan 
attributable to (1) Matching Contributions made by an 
Employer to this Plan for such Participant and (2) 
forfeitures applied pursuant to Section 6.7 to reduce the 
Matching Contributions which would otherwise have been made 
by an Employer for such Participant.

      (h)   "Company Thrift Account" means the account 
established and maintained under the Plan by the Committee 
to record a Participant's interest under this Plan 
attributable to contributions made by an Employer to the 
Thrift Plan for such Participant.

      (i)   "Company Stock" means the Class A Common Stock 
of the Company.

      (j)   "Compensation" shall mean the amount of 
compensation (within the meaning of Section 415(c) (3) of 
the Code) payable to a Participant for personal services 
rendered to an Employer.

      (k)   "Deferred Compensation Contribution" means a 
contribution made by an Employer to this Plan on behalf of a 
Participant pursuant to Section 3.1(b).

      (l)   "Employee" means any individual employed by an 
Employer.  Such term shall not include (1) lessees and 
sublessees of service stations and their employees, (2)





                                     -4-
<PAGE>   8
commission agents and their employees, (3) distributors and 
jobbers and their employees, (4) contractors and 
subcontractors and their employees,  or (5) any consultant 
or other person who under the normal practice of an  
Employer is not considered to be a regular employee.

      (m)   "Employee Stock Ownership Plan" means that 
Employee Stock Ownership Plan of American Petrofina, 
Incorporated as in effect prior to January 1, 1984.

      (n)   "Employer" shall include the Company and any 
other incorporated or unincorporated trade or business which 
may adopt this Plan with the consent of the Board of 
Directors of the Company.

      (o)   "Employment Date"  means the date an Employee 
first performs an Hour of Service after December 31, 1975; 
provided, however, that the Employment Date for any  
Employee employed by or on authorized leave of absence from 
an Employer or Affiliated Company on January 1, 1976 shall 
be the later of (1) such Employee's most recent date of 
commencing employment with an Employer or Affiliated  
Company prior to January 1, 1976, or (2) such Employee's 
most recent date prior to January 1, 1976 of making a 
complete withdrawal under the Thrift Plan.   If an Employee 
incurs a Break in Service after December 31, 1975, his 
Employment Date for the purposes of computing his  
subsequent Years of Service under the Plan shall be the





                                     -5-
<PAGE>   9
date he first performs an Hour of Service following his 
latest Break in Service.

      (p)   "ERISA" means the Employee Retirement Income 
Security Act of 1974, as amended from time to time, or any 
successor legislation which may hereafter be adopted in  
lieu thereof, and references herein to any specific 
provision of ERISA shall be deemed also to refer to the 
corresponding provision of ERISA as it may hereafter be so 
amended or replaced.

      (q)   "ESOP Account"  means the account established 
and maintained under this Plan by the Committee to record a 
Participant's interest under this Plan attributable to 
Company and Matching Employee Contributions made to the 
Employee Stock Ownership Plan for or by such Participant.

      (r)   "Government Bonds" means such class or classes 
of United States Government Bonds (including notes or  
Series E or similar savings bonds) as the Committee shall 
determine to be appropriate investments for the purposes of 
the Plan.

      (s)   "Hour of Service" means a hour for which an 
Employee is directly or indirectly compensated or entitled 
to compensation (including back pay, regardless of 
mitigation of damages) by an Employer for the performance  
of duties for an Employer or for reasons (such as vacation,




                                     -6-
<PAGE>   10
sickness or disability) other than the performance of  
duties for an Employer.  An Employee's Hours of Service 
shall be credited to the appropriate Service computation 
Periods determined in accordance with the provisions of 
Section 2530.200(b)-2b and (c) of the Department of Labor 
Regulations, which are incorporated herein by this 
reference.   In determining Hours of Service for the 
purposes of this Plan, periods of employment by an 
Affiliated Company shall be deemed to be periods of 
employment by an Employer.   The foregoing provisions of 
this definition to the contrary notwithstanding, each 
Employee who is not a vocational trainee or crude oil 
production pumper shall be credited with 190 Hours of 
Service for each month during which such Employee would 
otherwise be required to be credited with at least one Hour 
of Service under the foregoing provisions of this 
definition.

      (t)   "Matching Contribution" means a contribution 
made by an Employer to this Plan for a Participant pursuant 
to Section 3.2.

      (u)   "Net Profits" means an Employer's current 
profits or accumulated earned surplus as determined under 
generally accepted accounting principles and without regard 
to whether such Employer has current or accumulated  
earnings and profits for federal income tax purposes.




                                     -7-
<PAGE>   11
      (v)   "Nonvested Participant" means a Participant 
under the age of sixty-five years who has completed less 
than three Years of Service.

      (w)   "Partially Vested Participant" means a 
Participant under the age of sixty-five years who has 
completed at least three but less than five Years of 
Service.

      (x)   "Participant"  means an Employee who has become 
a Participant in this Plan in accordance with Section 2.1 
and whose Vested Interest under the Plan has not been fully 
distributed.

      (y)   "Participant Deferred Account"  means the 
account established and maintained under this Plan by the 
Committee to record a Participant's interest under this  
Plan attributable to Deferred Compensation Contributions 
made by an Employer to this Plan on behalf of such 
Participant.

      (z)   "Participant Thrift Account" means the account 
established and maintained under this Plan by the Committee 
to record a Participant's interest under this Plan 
attributable to (1) Thrift Contributions made by such 
Participant to this Plan,  (2) contributions made by such 
Participant to the Employee Stock Ownership Plan which were 
not Matching Employee Contributions thereunder, and (3) 
contributions made by such Participant to the Thrift Plan.




                                     -8-
<PAGE>   12
     (aa)   "PAYSOP Account" means the account established 
and maintained under this Plan by the Committee to record a 
Participant's interest under this Plan attributable to Tax 
Credit Contributions allocated to such Participant pursuant 
to this Plan.

     (bb)   "Permanent Disability" means the total and 
permanent incapacity of a Participant to perform the usual 
duties of his employment with an Employer or Affiliated 
Company as determined by the Committee.  Such incapacity 
shall be deemed to exist when certified by a physician who 
is acceptable to the Committee.

     (cc)   "Plan" means this Thrift and Employee Stock 
Ownership Plan to American Petrofina, Incorporated as 
effective January 1, 1984, and as in effect from time to 
time thereafter.

     (dd)   "Plan Year" means the calendar year.

     (ee)   "PSA Stock" means the common stock of  
Petrofina, S.A., a corporation organized under the laws of 
the Kingdom of Belgium.

     (ff)   "Retirement" means retirement under the 
provisions of a pension or retirement plan of an Employer  
or Affiliated Company on or after attaining the age of 
fifty-five years.

     (gg)   "Service Computation Period" means the period  
of twelve consecutive months commencing on an Employee's 
Employment Date or any anniversary thereof.




                                     -9-
<PAGE>   13
     (hh)   "Tax Credit Contribution" means a contribution 
made by an Employer pursuant to Section 3.3.

     (ii)   "Thrift Contribution" means a  contribution  
made by a Participant to this Plan pursuant to Section 
3.1(a).

     (jj)   "Thrift Plan"  means the Thrift Plan for 
Employees of American Petrofina, Incorporated and Certain 
Subsidiaries as in effect prior to January 1, 1984.

     (kk)   "Trust" means the trust fund established 
pursuant to Section 4.1.

     (ll)   "Trustee" means the individual and/or   
corporate trustee or trustees from time to time appointed 
and acting as trustee or trustees of the Trust.

     (mm)   "Vested Interest" means the portion of an 
Account under the Plan which is nonforfeitable at the 
particular point in time in question.

     (nn)   "Vested Participant" means a Participant who  
has either attained the age of sixty-five years or  
completed at least five Years of Service.

     (oo)   "Year of Service" means a Service Computation 
Period during which an Employee completes at least 1,000 
Hours of Service; provided, however, that a Service 
Computation Period during which an eligible Employee made  
no contribution to this Plan or the Thrift Plan shall be 
excluded in determining his Years of Service.  An Employee 




                                     -10-
<PAGE>   14
    shall also be credited with Years of Service for periods of   
    employment with a corporation any portion of the business     
    of which is acquired by an Employer by merger or otherwise,   
    to the extent such credit shall be determined by the Board    
    of Directors of the Company in its discretion to be given     
    on a uniform basis to all employees of such corporation.      

   Section 1.2  Construction.  The titles to the Articles and 
the headings of the Sections in this Plan are placed herein for 
convenience of reference only and in case of any conflict the  
text of this instrument, rather than such titles or headings, 
shall control.  Whenever a noun or pronoun is used in this Plan 
in plural form and there be only one person or entity within 
the scope of the words so used, or in singular form and there 
be more than one person or entity within the scope of the word 
so used, such word or pronoun shall have a plural or singular 
meaning as appropriate under the circumstance.  Masculine 
pronouns shall include their feminine counterparts and vice 
versa.

                          ARTICLE II.

                         PARTICIPATION

   Section 2.1  Participation.   Each Employee who was 
participating in the Thrift Plan or the Employee Stock 
Ownership Plan on December 31, 1983 shall be come a Participant 
in this Plan on January 1, 1984.  Each other Employee shall 
become a Participant of this Plan on the first day of any month 




                                     -11-
<PAGE>   15
coinciding with or next following the earliest anniversary of 
his Employment Date as of which he has completed a Year of 
Service; provided, however, that unless the Board of Directors 
of the Company shall otherwise provide on a basis uniformly 
applicable to all Employees similarly situated, no Employee 
shall become a Participant in this Plan if and so long as such 
Employee is a member of a collective bargaining unit the 
recognized representative of which has not agreed to 
participation in the Plan by members of such unit.  If an 
Employee who is already a Participant becomes a member of a 
collective bargaining unit the recognized representative of 
which has not agreed to participation in the Plan by members of 
such unit, such Participant shall remain a Participant in the 
Plan except that, any provision of this Plan to the contrary 
notwithstanding, no contribution to the Plan shall be made by, 
for or on behalf of such Participant so long as he continues to 
be a member of such unit.

                         ARTICLE III.

                 CONTRIBUTIONS AND ALLOCATIONS

   Section 3.1  Participant Elected Contributions.  Each 
Participant may, if he wishes, elect:

           (a)  to make a Thrift Contribution to the Plan for 
    each pay period in an amount equal to 1%, 2%, 3%, 4% or 5%  
    of his Basic Compensation for that pay period, and          




                                     -12-
<PAGE>   16
       (b)  to have his Employer make a Deferred Compensation 
    Contribution to the Plan for each pay period in an amount      
    equal to such whole percentage point of his Basic              
    Compensation as does not, when added to any Thrift             
    Contribution made by such Participant for that pay period,     
    exceed 10% of such Participant's Basic Compensation for        
    that pay period.                                               

Thrift Contributions shall be made by uniform payroll 
deductions which the Participant shall in writing authorize 
his Employer to withhold from his Basic Compensation and     
pay over to the Trustee.  Deferred Compensation Contributions 
shall be made by uniform payroll deductions pursuant to a  
Basic Compensation reduction agreement between the Participant 
and his Employer which authorizes the Employer to pay such 
contribution to the Trustee on behalf of the Participant.  A 
Participant may change the applicable percentage of payroll 
deductions as of any January 1, or as of any payday suspend  
for a period of at least six months his election to make  
Thrift Contributions or to have Deferred Compensation 
Contributions made on his behalf, provided (1) that written 
notice of such change or suspension is delivered to his 
Employer at least thirty days prior to the effective date 
thereof, and (2) that such a suspension may be made by a 
Participant only once within any period of thirty-six months.  
A Participant's elected contributions shall automatically 
resume upon the expiration of his designated




                                     -13-
<PAGE>   17
suspension period.  No retroactive contributions may be made by 
or on behalf of a Participant.

    Section 3.2  Employer Matching Contributions.  For each  
pay period an Employer shall, out of its Net Profits, make a 
Matching Contribution to the Plan for each Participant in its 
employ in an amount which, when added to any forfeiture amount 
being credited to such Participant for that pay period, will 
equal the lessor (1) 5% of such Participant's Basic 
Compensation for that pay period, or (2) the total amount of 
the Thrift and Deferred Compensation Contributions made by or 
on behalf of such Participant for that pay period.

    Section 3.3  Tax Credit Contributions.  For each Plan Year 
commencing after December 31, 1982, each Employer shall, out of 
its Net Profits, make a Tax Credit Contribution to the Plan in 
an amount equal to the following applicable percentage of the 
aggregate Compensation for that Plan Year of all Participants 
who were in the employ of such Employer on the last day of that 
year, or whose employment with such Employer terminated during 
that year by reason of death or by reason of retirement under 
the normal or early retirement or disability benefit provisions 
of a pension or retirement plan of an Employer or Affiliated 
Company:

<TABLE>
<CAPTION>
          For Plan Year          Applicable Percentage
          -------------          ---------------------
              <S>                        <C>
              1983                       0.50%   
              1984                       0.50%   
              1985                       0.75%   
</TABLE>                



                                     -14-
<PAGE>   18
<TABLE>
<CAPTION>
          For Plan Year          Applicable Percentage
          -------------          ---------------------
        <S>                              <C>
              1986                       0.75%     
              1987                       0.75%     
        1988 or thereafter               0.00%
</TABLE>     
          
The Tax Credit Contribution made to the Plan for a Plan Year 
shall be allocated among the Participants who were in the 
employ of an Employer on the last day of such year, or whose 
employment with such Employer terminated during that year by 
reasons of death or by reason of retirement under the normal or 
early retirement or disability benefit provisions of a pension 
or retirement plan of an Employer or Affiliated Company, in the 
proportion that the Compensation received by each such 
Participant during that year (disregarding any Compensation in 
excess of the first $100,000) bears to the Compensation 
received by all such Participants during that year 
(disregarding any Compensation in excess of the first $100,000 
for any Participant).

    Section 3.4  Payment to Trustee.  The Thrift and Deferred 
Compensation Contributions made to the Plan for a pay period 
ending within a particular month shall be paid to the Trustee 
in cash no later than thirty days after the end of such month.  
The Matching Contribution made to the Plan for a pay period 
ending within a particular month may be made in cash or in the 
form of Company Stock, or in any combination thereof, and shall 
be paid or transferred to the Trustee no later than thirty days 
after the end of such month.  The Tax Credit Contribution to be




                                     -15-
<PAGE>   19
made to the Plan for a particular Plan Year may be made in cash 
or in the form of Company Stock, or any combination thereof, 
and shall be paid or transferred to the Trustee no later than 
thirty days after the due date (including extensions thereof) 
for the filing of the Employers' federal income tax return for 
such year.  The value of any Company Stock contributed to the 
Plan as a Matching Contribution shall be the closing price of 
such stock on the open market as of the date of contribution if 
such stock was traded on the open market on such date, but if 
such stock was not traded on the open market as of the date of 
the contribution, then the value of the Company Stock shall be 
the closing price of such stock on the open market as of the 
date next preceding the date of the contribution that such 
stock was traded on the open market.  The value of any Company 
Stock contributed to the Plan as a Tax Credit Contribution 
shall be the average of the closing price of such stock, as 
reported on the composite tape for securities listed on the 
American Stock Exchange, Inc., for the twenty consecutive 
trading days immediately preceding the date on which such stock 
is contributed to the Plan.  If any Employer is prevented from 
making a contribution which it would otherwise have made under 
this Plan by reason of having no Net Profits or because such 
Net Profits are less than the contribution which it would 
otherwise have made, than so much of the contribution which 
such Employer was so prevented from making shall be made for




                                     -16-
<PAGE>   20
the benefit of the Participants in the employ of such Employer 
by the other Employers to the extent of their Net Profits in 
such proportions as such other Employers may determine.

    Section 3.5  Crediting of Contributions and Forfeitures.  
The Committee shall establish and maintain a Participant Thrift 
Account, a Company Thrift Account, a Participant Deferred 
Account, a Company Matching Account, an ESOP Account and a 
PAYSOP Account for each Participant.  All Thrift Contributions 
made by a Participant pursuant to Section 3.1(a), all Company 
Stock and other amounts attributable to contributions made by 
such Participant to the Thrift Plan, and all Company Stock and 
other amounts attributable to contributions made by such 
Participant to the Employee Stock Ownership Plan which were not 
Matching Employee Contributions thereunder, shall be allocated 
to such Participant's Participant Thrift Account under this 
Plan.  All Company Stock and other amounts attributable to 
Matching Contributions made by an Employer for a Participant 
pursuant to Section 3.2, and all forfeitures applied pursuant 
to Section 6.7 to reduce the Matching Contributions which would 
otherwise have been made by an Employer for such Participant, 
shall be credited to such Participant's Company Matching 
Account under this Plan.  All Company Stock, Company Class B





                                     -17-
<PAGE>   21
Common Stock and other amounts attributable to contributions 
made by an Employer to the Employee Stock Ownership Plan for a 
Participant, and all Company Stock, Company Class B Common 
Stock and other amounts attributable to contributions made by a 
Participant to the Employee Stock Ownership Plan which were 
Matching Employee Contributions thereunder, shall be credited 
to such Participant's ESOP Account under this Plan.  All Tax 
Credit Contributions allocated to a Participant pursuant to 
Section 3.3 shall be credited to such Participant's PAYSOP 
Account under this Plan.  All Deferred Compensation 
Contributions made by an Employer on behalf of a Participant 
pursuant to Section 3.1(b) shall be credited to such 
Participant's Participant Deferred Account; provided, however, 
that if for any Plan Year commencing after December 31, 1983, 
the actual deferral percentage for the highest paid one-third 
of all Employees eligible to elect to have their Employer make 
a Deferred Compensation Contribution to the Plan for them for 
that year fails to satisfy one of the following tests:

           (a)  the actual deferral percentage for said highest 
  paid one-third of such Employees is not more than the     
  actual deferral percentage for all other such Employees   
  multiplied by 1.5, or                                     

           (b)  the excess of the actual deferral percentage for 
  said highest paid one-third of all such Employees over the    
  actual deferral percentage for all other such Employees is    




                                     -18-
<PAGE>   22
    not more than three percentage points, and the actual  
    deferral percentage for said highest paid one-third of 
    such Employees is not more than the actual deferral 
    percentage  for all other such Employees multiplied by 2.5,
then the 10% maximum percentage of Basic Compensation otherwise 
permitted to be credited to the Participant Deferred Accounts 
of said highest paid one-third of such Employees shall be 
reduced in increments of one-half of one percent until the 
actual deferral percentage for said highest paid one-third of 
such Employees satisfies one of said tests.  For the purposes 
of this Section, the term "actual deferral percentage" for a 
specified group of Employees for a Plan Year means the average 
of the ratios (calculated separately for each Employee in such 
group) of (1) the sum of the amounts of the Deferred 
Compensation Contribution, the Tax Credit Contribution and the 
vested portion of the Matching Contributions (determined as of 
the last day of the Plan Year) made to the Plan for or on 
behalf of each such Employee for that year, to (2) the amount 
of such Employee's Compensation for that year.  Any Deferred 
Compensation Contribution made by an Employer on behalf of a 
Participant pursuant to Section 3.1(b) which cannot be credited 
to the Participant Deferred Account of such Participant because 
of the limitation contained in this Section shall be credited 
to such Participant's Participant Thrift Account.




                                     -19-
<PAGE>   23
                          ARTICLE IV.

                TRUST AND INVESTMENT PROVISIONS

    Section 4.1  Trust and Trustee.  All of the contributions 
and other amounts paid to the Trustee pursuant to this Plan, 
together with the income therefrom and the increments thereof, 
shall be held in trust by the Trustee under the terms and 
provisions of the separate trust agreement between InterFirst 
Bank Dallas, N.A., as Trustee, and the Employers, a copy of 
which is attached hereto and incorporated herein by this 
reference for all purposes, establishing a trust fund for the 
exclusive benefit of the Participants and their beneficiaries.

    Section 4.2  Investment of ESOP and PAYSOP Accounts.  All 
Tax Credit Contributions credited to a Participant's PAYSOP 
Account which are paid to the Trustee in cash shall be used by 
the Trustee within thirty days of receipt of purchase Company 
Stock for such Account.  All cash dividends, stock dividends, 
stock splits and other amounts received by the Trustee with 
respect to the Company Stock or other property held for an ESOP 
or PAYSOP Account shall be credited to (and, if cash or 
property other than Company Stock, used as soon as practicable 
to purchase Company Stock for) such Account.

    Section 4.3  Investment of Participant Thrift, Participant 
Deferred, Company Thrift and Company Matching Accounts.  Upon 
becoming a Participant in the Plan each Participant shall 
direct, on a form prescribed by and filed with the Committee, 
that:




                                     -20-
<PAGE>   24
    (a)  The contributions and other amounts credited to  his Participant
    Thrift and Participant Deferred Accounts be  invested, in percentage
    multiples authorized by the  Committee, in Company Stock, PSA Stock and/or
    Government  Bonds; and

    (b)  the contributions and other amounts credited to his Company
    Thrift and Company Matching Accounts be  invested, in percentage multiples
    authorized by the  Committee, in Company Stock and/or PSA Stock.

    If a Participant fails to give such investment direction, 
all contributions and other amounts credited to his Participant 
Thrift and Participant Deferred Accounts shall be invested in 
Government Bonds, and all contributions and other amounts 
credited to his Company Thrift and Company Matching Accounts 
shall be invested in Company Stock.  A Participant may change 
his investment direction with respect to future contributions 
or redirect the investment of one or more of said four Account 
balances on any January 1, provided that written notice of such 
change is delivered to the Committee at least thirty days prior 
to the January 1 as of which such change is to become 
effective.  All cash dividends, stock dividends, stock splits, 
interest and other amounts received by the Trustee with respect 
to a particular type of security held for a Participant Thrift, 
Participant Deferred, Company Thrift or Company Matching 
Account shall be credited to (and, if cash or property other 




                                     -21-
<PAGE>   25
than the security from which it was derived, used as soon as 
practicable to purchase said security for) such Account.

    Section 4.4  Purchases of Company and PSA Stock and 
Government Bonds.  Company Stock may be purchased by the 
Trustee in the open market or from the Company.  If Company 
Stock is purchased from the Company, the price of such Company 
Stock shall be the closing price of Company Stock on the open 
market as of the date of the purchase if such stock was traded 
on the open market on such date, or if such stock was not 
traded on the open market as of the date of the purchase, then 
the price of such Company Stock shall be the closing price of 
Company on the open market as of the date next preceding the 
date of the purchase that such stock was traded on the open 
market.  PSA Stock shall be purchased by the Trustee in the 
open market.  Investments in Government Bonds shall be made 
subject to such rules and regulations as may from time to time 
be established by the Committee.  Any cash in the hands of the 
Trustee at any time and not invested may be held by the Trustee 
for the Accounts of the Participants to whom it is attributable 
without obligation to credit interest thereon.  The Trustee 
shall add to the cost of securities purchased any brokerage 
commissions, transfer taxes and other charges or expenses 
incident thereto, or deduct from the gross proceeds from the 
sale of securities, any such charges incident thereto.  The 
cost to a Participant's Account of securities purchased shall




                                     -22-
<PAGE>   26
be the average cost of all securities of the particular issue 
purchased by the Trustee during the calendar month in which the 
securities shall have been purchased for Participants' 
Accounts.  In case of the redemption of any nontransferrable 
Government Bond or on the maturity thereof, the Participant for 
whose Account such Government Bond was purchased shall take 
such steps as the Trustee may prescribe in order to effect the 
redemption or collection thereof by the Trustee.

    Section 4.5  Voting Rights.  Each Participant shall be 
entitled to direct the Trustee as to the manner in which any 
rights (including but not limited to voting rights, 
subscription rights and conversion privileges) with respect to 
the Company Stock and Company Class B Common Stock credited to 
such Participant's ESOP and PAYSOP Accounts are to be 
exercised.  For this purpose, the Committee shall notify each 
Participant of each annual or special meeting of the 
shareholders of the Company and of any other occasion for the 
exercise of voting or other rights by such shareholders, not 
later than the date prior to such meeting or other occasion on 
which the Company notifies its other shareholders.  The 
notification shall include a copy of any proxy solicitation 
material and other information which the Company distributes to 
shareholders regarding the exercise of voting or other rights, 
together with a form requesting instructions to the Trustee as 
to how the Participant's rights are to be exercised.  The 




                                     -23-
<PAGE>   27
Trustee shall tabulate the instructions received and shall vote 
or otherwise exercise rights with respect to said shares of 
stock as instructed.  The Trustee shall not vote or otherwise 
exercise rights with respect to any of said shares of stock as 
to which no instructions from Participants have been duly 
received.

                          ARTICLE V.

                VESTING AND DISTRIBUTION EVENTS

    Section 5.1  Retirement or Disability.   Upon the 
Retirement of a Participant or in the event of a Participant's 
Permanent Disability while employed by or on authorized leave 
of absence from an Employer or Affiliated Company, the amounts 
credited to all Accounts maintained for such Participant shall 
be fully vested and distributed to him in accordance with the 
provisions of Article VI.

    Section 5.2  Death.  Upon the death of a Participant, the 
amounts credited to all Accounts maintained for such 
Participant shall be fully vested and distributed to his 
beneficiary or beneficiaries in accordance with the provisions 
of Article VI.

    Section 5.3  Break in Service.  If a Participant incurs a 
Break in Service prior to his Retirement, Permanent Disability 
or death, such Participant shall be entitled to receive the 
full amount credited to his Participant Thrift, Participant 
Deferred ESOP and PAYSOP Accounts, plus the following portion 




                                     -24-
<PAGE>   28
of the amount credited to his Company Thrift and Company 
Matching Accounts, depending upon the number of Years of 
Service completed by such Participant on the date of such 
separation from employment:

          Years of Service           Percentage Vested
          ----------------           -----------------
             Less Than 3                   None
                 3                          60%
                 4                          80%
             5 or More                     100%

provided, however, that notwithstanding the foregoing schedule, 
a Participant's Company Thrift and Company Matching Accounts 
shall be fully vested on and after  the day such  Participant 
is entitled to receive under this Section shall be distributed 
to such Participant in accordance with the provisions of 
Article VI, and the balance of such Participant's Company 
Thrift and Company Matching Accounts shall be forfeited.


                          ARTICLE VI.

                 DISTRIBUTIONS AND FORFEITURES

    Section 6.1  Time and Form of Distribution.  The 
distribution of amounts withdrawn by or otherwise due to a 
Participant or beneficiary under the Plan shall be made as soon 
as practicable after such Participant or beneficiary becomes 
entitled to distribution, but unless the Participant elects 
otherwise with the consent of the Committee, in no event later 
than sixty days after the end of the Plan Year during which  




                                     -25-
<PAGE>   29
such Participant or beneficiary becomes entitled to such 
distribution.  The portion of any Account invested in 
Government Bonds will be distributed in the form of such bonds 
or in cash, or in any combination thereof, as determined by the 
Committee in its absolute discretion.  The portion of any 
Account (other than an ESOP or PAYSOP Account) invested in 
Company stock will be distributed in the form of such stock or 
in cash, or in any combination thereof, as determined by the 
Committee in its absolute discretion.  The portion of any 
Account invested in PSA Stock will be converted into cash and 
distributed in the form of cash or in the form of Company 
Stock, or in any combination thereof, as determined by the 
Committee in its absolute discretion.  All amounts credited to 
an ESOP or PAYSOP Account will be distributed in the form of 
Company Stock (with cash in lieu of fractional shares).  If any 
portion of an ESOP Account is invested in shares of Company 
Class B Common Stock and a withdrawal or other distribution 
event occurs with respect to said shares, prior to any 
distribution from such ESOP Account the Participant or 
beneficiary to whom such distribution would otherwise be made 
shall instruct the Trustee in writing either to "put" said 
shares of stock to the Company for cash or to exchange said 
shares of stock with the Company for Company Stock on a 
share-for-share basis.  If the "put" is elected, the per share 
value of Company Class B Common Stock shall be deemed to be




                                     -26-
<PAGE>   30
equal to the average closing price per share of Company Stock, 
as reported on the composite tape for securities listed on the 
American Stock Exchange, Inc., for the twenty consecutive 
trading days immediately preceding the date on which such "put" 
is exercised.  Any Company or PSA Stock which is to be 
converted into cash for distribution to a Participant or 
beneficiary shall be sold by the Trustee in the open market 
during the month following the date as of which such withdrawal 
or other distribution event occurs.  The amount of cash to be 
distributed to the Participant or beneficiary with respect to 
such Company or PSA Stock shall be determined on the basis of 
the average net proceeds per share (i.e., gross proceeds from 
the sale less any brokerage commissions, transfer taxes and 
other expenses incident thereto) realized by the Trustee upon 
such sales during said month.  In lieu of making such sale in 
the open market, the Trustee in its discretion may match such 
sales with purchases to be made for such month pursuant to the 
Plan, with the prices of any such matched sales and purchases 
being determined in the same manner as provided in section 4.4 
for determining the price of Company Stock purchased from the 
Company.

    Section 6.2  Distribution of Retirement, Disability and 
Death Benefits.  Any amount payable to a Participant under the 
Plan upon his Retirement or Permanent Disability shall be 
distributed to such Participant in a single distribution.  Any




                                     -27-
<PAGE>   31
amount payable under the plan upon the death of a Participant 
shall be distributed in a single distribution to the 
beneficiary or beneficiaries designated by such Participant.  
Such designation of beneficiary or beneficiaries shall be made 
in writing on a form prescribed by the Committee and, when 
filed with the Committee, shall become effective and remain in 
effect until changed by the Participant by the filing of a new 
beneficiary designation from with the Committee.  If a 
Participant fails to so designate a beneficiary, or in the 
event all of the designated beneficiaries are individuals who 
predeceased the Participant, then the Committee shall direct 
the Trustee to distribute the amount payable under the Plan in 
a single distribution to the estate of such deceased 
Participant.

    Section 6.3  Withdrawals by Vested Participants.  Subject 
to such conditions, limitations and procedures as the Committee 
may from time to time prescribe for application to all Vested 
Participants on a uniform and nondiscriminatory basis, by 
filing a written notice of withdrawal with the Committee prior 
to the end of any month a Vested Participant may withdraw:

         (a)(1)  all or any portion of the amount credited to 
         his Participant Thrift Account as of the end of such month, 
         and (2) if no amount will remain credited to his 
         Participant Thrift Account following such withdrawal, all 
         or any portion of the amount credited to his Company Thrift




                                     -28-
<PAGE>   32
Account as of the end of such month, and if such 
Participant has either attained the age of 59-1/2 years or 
is not in the employ of or on authorized leave of absence 
from an Employer or Affiliated Company, all or any portion 
of the amounts credited to his Participant Deferred and 
Company Matching Accounts as of the end of such month;

     (b)  from his ESOP Account, (1) all or any portion of 
(i) the Company Stock and/or Company Class B Common Stock 
representing Employer contributions which have been 
allocated to such Account (or such Participant's Account 
under the Employee Stock Ownership Plan) as of the end of 
such month for a period of at least 84 months after the 
month as of which such allocation was made, (ii) the 
Company Stock and/or Company Class B Common Stock 
representing Participant contributions which have been 
allocated to such Account (or such Participant's Account 
under the Employee Stock Ownership Plan) as of the end of 
such month for a period of at least 84 months after the 
month as of which such allocation was made, and (iii) the 
Company Stock which has been purchased with Trust income or 
represents dividends paid in Company Stock and which has 
been credited to such Account as of the end of such month, 
or (2) if such Participant is not in the employ of or on 
authorized leave of absence from an Employer or Affiliated 
Company at the end of such month, all (but not less than 




                                     -29-
<PAGE>   33
all) of the Company Stock and Company Class B Common Stock 
credited to such Account;

     (c)  form his PAYSOP Account, (1) if he has attained 
the age of 59-1/2 years, all or any portion of (i) the 
Company Stock representing Employer contributions which 
have been allocated to such Account as of the end of such 
month for a period of at least 84 months after the month as 
of which such allocation was made, and (ii) the Company 
Stock which has been purchased with Trust income or 
represents dividends paid in Company Stock and which has 
been credited to such Account as of the end of such month, 
or (2) if such Participant is not in the employ of or on 
authorized leave of absence from an Employer or Affiliated 
Company at the end of such month, all (but not less than 
all) of the Company Stock credited to such Account;

     (d)  from his Participant Deferred and Company 
Matching Accounts, if such notice of withdrawal requests a 
distribution to alleviate a hardship (within the meaning of 
Section 401(k)(2)(B) of the Code and the regulations 
promulgated thereunder) of such Vested Participant which is 
evidenced to the satisfaction of the Committee, such amount 
as the Committee shall determine to be necessary to meet 
the immediate financial need created by said hardship and 
not reasonably available from other sources.




                                     -30-
<PAGE>   34
     Section 6.4  Withdrawals by Partially Vested Participants
Subject to such conditions, limitations and procedures as the 
Committee may from time to time prescribe for application to 
all Partially Vested Participants on a uniform and 
nondiscriminatory basis, a Partially Vested Participant may 
withdraw all (but not less than all) of the aggregate value of 
his Participant Thrift Account and the vested portion of his 
Company Thrift Account as of the end of any month by filing a 
written notice of such withdrawal with the Committee prior to 
the end of such month.  Any provision of this Plan to the 
contrary notwithstanding:

         (a)  if the Partially Vested Participant making a 
         withdrawal pursuant to this Section is in the employ of or 
         on authorized leave of absence from an Employer or 
         Affiliated Company at the end of the month as of which such 
         withdrawal is made, (1) no Thrift, Deferred Compensation or 
         Matching Contributions shall be made by, for or on behalf 
         of such Partially Vested Participant for a period of six 
         months following the month as of the end of which such 
         withdrawal was made, and (2) the vested portion of such 
         Participant's Company Thrift Account at all times after the 
         making of such withdrawal shall be determined by the 
         formula P(AB+D)-D, where P is such Participant's vested 
         percentage at the relevant time, AB is the value of said 
         Account at the relevant time, and D is the total amount 
         previously withdrawn from said Account; or




                                     -31-
<PAGE>   35
        (b)  if the Partially Vested Participant making a  withdrawal pursuant
    to this Section is not in the employ of  or on authorized leave of absence
    from an Employer or Affiliated Company at the end of the month as
    of which such  withdrawal is made, upon such withdrawal the unvested 
    portion of such Partially Vested Participant's Company  Thrift Account
    shall be forfeited; provided, however, that  if such Partially Vested
    Participant repays the full amount  of such withdrawal prior to incurring a
    Break in Service  and within two years of the date he is first credited
    with  an Hour of Service following such withdrawal, the amount so 
    forfeited shall be restored to his Company Thrift Account  by an additional
    Employer contribution.

    In addition to the foregoing, a Partially Vested 
Participant who is not in the employ of or on authorized leave 
of absence from an Employer or Affiliated company may withdraw 
all (but not less than all) of the Company Stock and Company 
Class B Common Stock credited to his ESOP and PAYSOP Accounts, 
and all (but not less than all) of the aggregate value of his 
Participant Deferred Account and the vested portion of his 
Company Matching Account .  Upon the withdrawal by a Partially 
Vested Participant of said aggregate value of his Participant 
Deferred Account and the vested portion of his Company Matching 
Account, the unvested portion of his Company Matching Account 
shall be forfeited; provided, however, that if such Partially




                                     -32-
<PAGE>   36
Vested Participant repays the full amount of such withdrawal 
prior to incurring a Break in Service and within two years of 
the date he is first credited with an Hour of Service following 
such withdrawal, the amount so repaid shall be credited to his 
Participant Thrift Account and the amount so forfeited shall be 
restored to his Company Thrift Account by an additional 
Employer contribution.

    Section 6.5  Withdrawals by Nonvested Participants.
Subject to such conditions, limitations and procedures as the 
Committee may from time to time prescribe for application to 
all Nonvested Participants on a uniform and nondiscriminatory 
basis, a Nonvested Participant may withdraw all (but not less 
than all) of the value of his Participant Thrift Account as of 
the end of any month by filing a written notice of such 
withdrawal with the Committee prior to the end of such month.  
Any provision of this Plan to the contrary notwithstanding, if 
a Nonvested Participant makes a withdrawal pursuant to this 
Section:

              (a)  no Thrift, Deferred Compensation or Matching 
         Contributions shall be made by, for on behalf of such 
         Nonvested Participant for a period of six months following 
         the month as of the end of which such withdrawal was made;
         and

              (b)  upon the making of such withdrawal the entire 
         value of such Nonvested Participant's Company Thrift 




                                     -33-
<PAGE>   37
    Account shall be forfeited; provided, however, that if such  Nonvested
    Participant repays the full amount of such  withdrawal prior to incurring a
    Break in Service and within two years of the date he is first
    credited with an Hour of  Service following such withdrawal, the amount so
    forfeited  shall be restored to his Company Thrift Account by an 
    additional Employer contribution.

    In addition to the foregoing, a Nonvested Participant who 
is not in the employ of or on authorized leave of absence from 
an Employer or Affiliated Company may withdraw all (but not 
less than all) of the Company Stock and Company Class B Common 
Stock credited to his ESOP and PAYSOP Accounts, and all (but 
not less than all) of the value of his Participant Deferred 
Account.  Upon the withdrawal by a Nonvested Participant of the 
value of his Participant Deferred Account, the entire value of 
his Company Matching Account shall be forfeited; provided, 
however, that if such Nonvested Participant repays the full 
amount of such withdrawal prior to incurring a Break in Service 
and within two years of the date he is first credited with an 
Hour of Service following such withdrawal, the amount so repaid 
shall be credited to his Participant Thrift Account and the 
amount so forfeited shall be restored to his Company Thrift 
Account by an additional Employer contribution.

    Section 6.6  Break in Service Distribution.  The Vested 
Interest of a Participant which has not been previously




                                     -34-
<PAGE>   38
distributed or withdrawn in accordance with the provisions of 
this Article shall be distributed in a single distribution to 
such Participant upon his incurring a Break in Service.  The 
then unvested portions of a Participant's Company Thrift and 
Company Matching Accounts shall be permanently forfeited when 
he incurs a Break in Service.

    Section 6.7  Application of Forfeitures.  Any forfeitures 
resulting under the provisions of this Article shall be 
credited to a Forfeiture Account and thereafter applied to 
reduce the earliest subsequent Matching Contributions the 
Employers would otherwise be required to make to the Plan: 
provided, however, that if the Plan is terminated, any 
forfeited amounts not then so applied shall be credited ratably 
among the Accounts (other than ESOP and PAYSOP Accounts) 
remaining in the Plan at the time of such termination.

    Section 6.8  Distributions to Minors and Persons Under 
Legal Disability.  If any distribution under the Plan becomes 
payable to a minor or other person under a legal disability, 
such distribution shall be made to the duly appointed guardian 
or other legal representative of the estate of such minor or 
person under legal disability.

                          ARTICLE VII

                      PLAN ADMINISTRATION

    Section 7.1  Appointment of Committee.  This Plan shall be 
administered on behalf of all Employers by a Committee composed 




                                     -35-
<PAGE>   39
of at least three individuals appointed by the Board of 
Directors of the Company.  Each member of the Committee so 
appointed shall serve in such office until his death, 
resignation or removal by the Board of Directors of the 
Company.  The Board of Directors of the Company may remove any 
member of the Committee at any time by giving written notice 
thereof to the members of the Committee.  Vacancies shall 
likewise be filled from time to time by the Board of Directors 
of the Company.  The members of the Committee shall receive no 
remuneration from the Plan for their services as Committee 
members.

    Section 7.2  Powers and Duties of the Committee.  The 
Committee shall interpret and implement the provisions of the 
Plan, and shall perform all of the duties and may exercise all 
of the powers and discretion granted to it under the terms of 
the Plan.  The Committee shall act by a majority of its members 
at the time in office and such action may be taken either by a 
vote at a meeting or in writing without a meeting.  The 
Committee may by such majority action authorize any one or more 
of its members to execute any document or documents on behalf 
of the Committee, in which event the Committee shall notify the 
Trustee in writing of such action and the name or names of its 
member or members so authorized to act.  Every interpretation, 
choice, determination or other exercise by the Committee of any 
power or discretion given either expressly or by implication to




                                     -36-
<PAGE>   40
it shall be conclusive and binding on all parties directly or 
indirectly affected, without restriction, however, on the right 
of the Committee to reconsider and redetermine such actions.  
In performing any duty or exercising any power herein 
conferred, the Committee shall in no event perform such duty or 
exercise such power in any manner which discriminates in favor 
of Employees who are officers, shareholders or highly 
compensated employees of an Employer.

    Section 7.3  Rules, Records and Reports.   The Committee 
may adopt such rules and regulations for the administration of 
the Plan as are consistent with the terms hereof, and shall 
keep adequate records of its proceedings and acts and of the 
status of the Participants' Accounts.  The Committee may employ 
such agents, accountants and legal counsel (who may be agents, 
accountants or legal counsel for an Employer) as may be 
appropriate for the administration of the Plan.  The Committee 
shall annually provide each Participant with a report 
reflecting the status of his Accounts under the Plan and shall 
cause such other information, documents or reports to be 
prepared, provided and/or filed as may be necessary to comply 
with the provisions of the Code, ERISA or other applicable law.

    Section 7.4  Administration Expenses and Taxes.   Unless 
otherwise paid by the Employers in their discretion, the 
Committee shall direct the Trustee to pay all reasonable and 
necessary expenses (including the fees of agents, accountants




                                     -37-
<PAGE>   41
and legal counsel) incurred by the Committee in connection with 
the administration of the Plan.  Should any tax of any 
character (including transfer taxes) be levied upon the Trust 
assets or the income therefrom, such tax shall be paid from and 
charged against the assets of the Trust.

    Section 7.5  Claims Procedure.   If any Participant or 
beneficiary (hereinafter called the "claimant") feels that he 
is being denied a benefit to which he is entitled under the 
Plan, such claimant may file a written claim for said benefit 
with any member of the Committee.  Within sixty days after the 
receipt of such claim the Committee shall determine and notify 
the claimant as to whether he is entitled to such benefit.  
Such notification shall be in writing and, if denying the claim 
for benefit, shall set forth the specific reason or reasons for 
the denial, make specific reference to the pertinent provisions 
of the Plan, and advise the claimant that he may, within sixty 
days of the receipt of such notice, in writing request to 
appear before the Committee or its designated representative 
for a hearing to review such denial.  Any such hearing shall be 
scheduled at the mutual convenience of the Committee or its 
designated representative and the claimant, and at such hearing 
the claimant and/or his duly authorized representative may 
examine any relevant documents and present evidence and 
arguments to support the granting of the benefit being
claimed.  The final decision of the Committee with respect to




                                     -38-
<PAGE>   42
the claim being reviewed shall be made within sixty days 
following the hearing thereon and the Committee shall in 
writing notify the claimant of its final decision, again 
specifying the reasons therefor and the pertinent provisions of 
the Plan upon which such decision is based.  The final decision 
of the Committee shall be conclusive and binding upon all 
parties having or claiming to have an interest in the claim 
being reviewed.

                         ARTICLE VIII.

                   AMENDMENT AND TERMINATION

    Section 8.1  Amendment.  The Company shall have the right 
and power at any time and from time to time to amend this Plan, 
in whole or in part, on behalf of all Employers.  With the 
consent of the company, each Employer shall have the right and 
power at any time and from time to time to amend this Plan, in 
whole or in part, with respect to the Plan's,  application to 
the Participants of the particular amending Employer and the 
assets held in the Trust for their benefit, or to transfer such 
assets or any portion thereof to a new trust for the benefit 
of such Participants.  However, in no event shall any amendment 
or new trust permit any portion of the trust fund to be used 
for or diverted to any purpose other than the exclusive benefit 
of the Participants and their beneficiaries, nor shall any 
amendment or new trust deprive any Participant of his Vested 
Interest under the Plan.  The Employers shall in writing notify 




                                     -39-
<PAGE>   43
the Committee of any amendment or change in the provisions of 
the Plan.

    Section 8.2  Termination.   Each Employer may at any time 
terminate this Plan as it applies to the Participants of such 
Employer by giving written notice thereof to the Committee and 
Trustee.  Any provisions of this Plan to the contrary 
notwithstanding, upon the termination or partial termination of 
the Plan as to any Employer, or in the event any Employer 
should completely discontinue making contributions to the Plan 
without formally terminating it, all amounts credited to the 
Accounts of the affected participants of that particular 
Employer shall be fully vested and nonforfeitable.

                          ARTICLE IX.

               MISCELLANEOUS GENERAL PROVISIONS

    Section 9.1  Spendthrift Provision.   No right or interest 
of any Participant or beneficiary under this Plan may be 
assigned, transferred or alienated, in whole or in part, either 
directly or by operation of law, and no such right or interest 
shall be liable for or subject to any debt, obligation or 
liability of such Participant or beneficiary.

    Section 9.2  Maximum Annual Additional Limitation.   Any 
provision of this Plan to the contrary notwithstanding, the sum 
of (a) the Employer contributions, (b) the lesser of one-half 
of the Participant's contributions (excluding rollover 
contributions) or the Participant's contributions (excluding 




                                     -40-
<PAGE>   44
rollover contributions) in excess of 6% of Compensation and (c) 
the forfeitures allocated to the Accounts of any Participant 
with respect to a Plan Year shall in no event exceed the lesser 
of $30,000 adjusted to take into account any cost-of-living 
adjustment authorized pursuant to Section 415(d) of the Code, 
or 25% of such Participant's Compensation for that year.  For 
the purposes of applying the limitation imposed by this 
Section, an Employer and its Affiliated Companies shall be 
considered a single employer, and all defined contribution 
plans (meaning plans providing for individual accounts and 
benefits based solely on the amounts contributed to such 
accounts and any forfeitures, income, expenses, gains and 
losses allocated to such accounts) described in Section 415(k) 
of the Code, whether or not terminated, maintained by an 
Employer or an Affiliated Company shall be considered a single 
plan.  If the total amount allocable to a Participant's 
Accounts for a Plan Year would, but for this sentence, exceed 
the limitation imposed by this Section, such Participant's 
Thrift Contributions for such year (with the Deferred 
Compensation Contributions made on behalf of such Participant 
for that year being reclassified as Thrift Contributions to the 
extent necessary) shall be refunded to such Participant to the 
extent necessary to permit the maximum permissible allocation 
of ESOP and Matching Contributions to such Participant for that 
year.  Any remaining amount which cannot be allocated to a




                                     -41-
<PAGE>   45
particular Participant for a Plan Year because of the 
limitation imposed by this Section shall be credited to a 
Suspense Account and thereafter reallocated (prior to the 
allocation of forfeitures) to reduce the earliest subsequent 
Matching Contributions the Employers would otherwise be 
required to make to the Plan.

    Section 9.3  Limitations on Responsibilities.  The 
Employers do not guarantee or indemnify the Trust against any 
loss or depreciation of its assets which may occur, nor 
guarantee the payment of any amount which may become payable to 
a Participant or his beneficiaries pursuant to the provisions 
of this Plan.  All payments to Participants and their 
beneficiaries shall be made by the Trustee at the direction of 
the Committee solely from the assets of the Trust and the 
Employer shall have no legal obligation, responsibility or 
liability for any such payments.

    Section 9.4  Committee Indemnification.  The Company will 
indemnify and hold harmless each member of the Committee 
against any claim, cost, expense (including attorney's fees), 
judgment or liability (including any sum paid in settlement of 
a claim with the approval of the Company) arising out of any 
act or omission to act as a member of the Committee under this 
Plan, except in the case of willful misconduct.

    Section 9.5  Employment Noncontractual.  The establishment 
of this Plan shall not enlarge or otherwise affect the terms of




                                     -42-
<PAGE>   46
any Employee's employment with an Employer and an Employer may 
terminate the employment of any Employee as freely and with the 
same effect as if this Plan had not been adopted.

    Section 9.6  Merger or Consolidation.  In no event shall 
this Plan be merged or consolidated into or with any other 
plan, nor shall any of its assets or liabilities be transferred 
to any other plan, unless each Participant would be entitled to 
receive a benefit if the plan in which he then participates 
terminated immediately following such merger, consolidation or 
transfer, which is equal to or greater than the benefit he 
would have been entitled to receive if the Plan had been 
terminated immediately prior to such merger, consolidation or 
transfer.

    Section 9.7  Employee Stock Ownership Plan Merger Into 
Thrift Plan.  The merger of the Employee Stock Ownership Plan 
into the Thrift Plan as contemplated in this Plan is contingent 
upon receiving a determination letter from the Internal Revenue 
Service that this Plan and its related Trust qualify under the 
provisions of Sections 401(a) and (k), 409A and 501(a) of the 
Code.  Any provision of this Plan to the contrary 
notwithstanding, if such determination cannot be obtained 
without the making of amendments to the Plan or its related 
Trust which the Company is unwilling to make, then this Plan 
and its related Trust shall be null and void and the Employee 
Stock Ownership Plan, the Thrift Plan and their respective




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<PAGE>   47
trust agreements shall remain in full force and effect in 
accordance with their respective terms as in effect on December 
31, 1983, with all Thrift and Deferred Compensation 
Contributions made hereunder being considered to have been made 
by Participants to the Thrift Plan, with all Matching 
Contributions made hereunder being considered to have been made 
by the Employers to the Thrift Plan, and with all Tax Credit 
Contributions made hereunder being considered to have been made 
to the Employee Stock Ownership Plan.

    Section 9.8  Applicable Law.  This Plan shall be governed 
and construed in accordance with the laws of the State of Texas 
except where superseded by federal law.

    IN WITNESS WHEREOF, this Plan has been executed at Dallas, 
Texas, on this ______  day of __________________, 1983, to be 
effective as of January 1, 1984.




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