<PAGE> 1                                                        
							
							Exhibit 2.1


	ASSIGNMENT AND ASSUMPTION AGREEMENT, dated as of October 4, 1996 
	(the "Agreement"), among Clark Refining & Marketing, Inc. ("Assignor"), 
	a Delaware corporation, J. ARON & COMPANY ("Assignee"), a New York 
	partnership, Clark USA, Inc. ("Clark USA"), a Delaware corporation, 
	and, solely for the limited purposes of Sections 4.06, 4.08, 4.10 and 
	4.12(a) hereof and no other, each of Occidental Petroleum Corporation 
	("OPC"), a Delaware corporation, Occidental C.O.B. Partners ("OCP"), 
	a Delaware general partnership, and Occidental Crude Sales, Inc. 
	(International) ("OCS") , a Delaware corporation. 

	WHEREAS, the Assignor is a party to certain agreements set forth on 
	Annex A and it desires to assign to Assignee, and Assignee desires 
	to assume from Assignor, such agreements. 

	WHEREAS, the Assignor acquired such agreements from Clark USA pursuant 
	to an Assignment and Assumption Agreement dated as of October 3, 1996 
	between Clark USA and Assignor (the "USA Assignment" and, together with 
	this Agreement, the "Agreements").

	NOW THEREFORE, in consideration of the foregoing and the respective 
	representations, warranties, covenants and agreements set forth in this 
	Agreement, the parties agree as follows:

				    I. ASSIGNMENT AND ASSUMPTION

	SECTION 1.01.  Assignment and Assumption.  (a)  For and in consideration 
	of the Purchase Price (as defined below) the receipt whereof is hereby 
	acknowledged by the Assignor, the Assignor does hereby sell, assign and 
	transfer to the Assignee, effective as of 11:59 p.m. (the "Effective 
	Time") on October 3, 1996 (the "Effective Date"), all of the Assignor's 
	right, title and interest (i) in the agreements listed on Annex A annexed 
	hereto (hereinafter referred to, individually and collectively, as the 
	"Instruments") and (ii) in the USA Assignment.

	(b)  The Assignee does hereby, for the benefit of the Assignor and the 
	other parties to the Instruments, accept this assignment and expressly 
	assume and agree to hereafter perform, observe and abide by all of the 
	terms, covenants, conditions and obligations under the Instruments on the 
	part of the Assignor to be kept, observed and performed thereunder, and 
	the Assignee does hereby agree to defend and indemnify the Assignor, and 
	save the Assignor and its successors harmless, of and from any and all 
	demands, claims, actions or causes of action, assessments, expenses, 
	costs, damages, losses and liabilities, including reasonable attorneys' 
	fees and disbursements, that the Assignor or the Assignor's successors 
	may sustain or incur as a result of the failure of the Assignee, or 

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	those claiming under or through the Assignee, from and after the 
	Effective Time on the Effective Date, to keep, observe and perform any 
	of the terms, covenants, conditions and obligations under the 
	Instruments that are to be observed or performed from and after the 
	Effective Time.

	SECTION 1.02.  Purchase Price.  The "Purchase Price" is $235,400,000.00 
	in immediately available funds delivered by wire transfer to an account 
	designated by Assignor. 

		      II.  REPRESENTATIONS AND WARRANTIES OF ASSIGNOR

	As an inducement to Assignee to enter into this Agreement, each of 
	Assignor and Clark USA hereby represents and warrants to Assignee as of 
	the Effective Time on the Effective Date as follows (such 
	representations and warranties to survive (i) for a period of six 
	months after the Effective Time on the Effective Date in the case of 
	Sections 2.01, 2.02, 2.03, 2.04 and 2.06, and (ii) into perpetuity in 
	the case of Section 2.05) (provided, however, that the representations 
	and warranties made by Assignor with respect to Sections 2.01, 2.02, 
	2.03 and 2.04 are made only with respect to itself):

	SECTION 2.01.  Organization and Authority of Assignor.  Each of 
	Assignor and Clark USA is a corporation duly organized, validly existing 
	and in good standing under the laws of Delaware and has all necessary 
	power and authority to enter into this Agreement and the USA Agreement, 
	to carry out its obligations hereunder and thereunder and to consummate 
	the transactions contemplated hereby and thereby.  The execution and 
	delivery of each of the Agreements by Assignor and Clark USA, the 
	performance by Assignor and Clark USA of its obligations under the 
	Agreements and the consummation by Assignor and Clark USA of the 
	transactions contemplated by the Agreements have been duly authorized 
	by all requisite action on the part of Assignor and Clark USA.  Each 
	Agreement has been duly executed and delivered by Assignor and Clark 
	USA, and (assuming due authorization, execution and delivery by the 
	other parties hereto in the case of this Agreement) each Agreement 
	constitutes legal, valid and binding obligations of Assignor and Clark 
	USA enforceable against Assignor and Clark USA in accordance with its 
	terms.

	SECTION 2.02.  No Conflict.  The execution, delivery and performance 
	of the Agreements by Assignor and Clark USA does not and will not (a) 
	violate, conflict with or result in the breach of any provision of the 
	certificate of incorporation or by-laws of Assignor or Clark USA, (b) 
	conflict with or violate any law or governmental order applicable to 
	Assignor or Clark USA, or (c) conflict with, result in any breach of, 
	constitute a default (or event which with the giving of notice or lapse 
	of time, or both, would become a default) under, require any consent 
	under, or give to others any rights of termination, 
	
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	amendment, acceleration, suspension, revocation or cancellation of any 
	of the Instruments or of any other agreement binding on or affecting 
	Assignor or Clark USA or any of either of their assets.

	SECTION 2.03.  No Default.  Each of the Instruments to which Assignor 
	or Clark USA is a party is in full force and effect and is Assignor's 
	or Clark USA's, as applicable, legal, valid and binding obligation, 
	enforceable against Assignor or Clark USA, as applicable, in accordance 
	with the terms thereof. To Assignor's and Clark USA's best knowledge, no 
	party to an Instrument is in default thereunder or has breached any 
	terms or provisions thereof.  No third party has given Assignor or Clark 
	USA notice of any claim, dispute or controversy with respect to any of 
	the Instruments nor has Assignor or Clark USA received notice of alleged 
	nonperformance, or other noncompliance by Assignor or Clark USA with 
	respect to Assignor's and Clark USA's obligations under any of the 
	Instruments.  Neither Assignor or Clark USA is in default under any of 
	the Instruments or has breached any terms or provisions thereof.  The 
	Instruments have not been amended or supplemented by agreement, course 
	of conduct or otherwise, other than (i) by the Agreements, (ii) the 
	reports and notices referenced in Section 2.06 hereof and (iii) notices 
	delivered to Clark USA in connection with the matters referred to in 
	Section 4.08 and no waivers have been granted thereunder.  There are no 
	other agreements or instruments that vary the terms of any of the 
	Instruments.  Attached hereto as Annex B are true, correct and complete 
	copies of the Instruments.

	SECTION 2.04.  Title; No Liens   (a)  Immediately prior to the 
	Effective Time on the Effective Date, Assignor had good and marketable 
	title to each of the Instruments free and clear of any liens, claims 
	or encumbrances of any kind (each, a "Lien"), including but not limited 
	to any Lien of Universal Exchange Corporation ("UEC"), and the Assignor 
	is hereby transferring to the Assignee pursuant to this Agreement, good 
	and marketable title to each of the Instruments free and clear of any 
	Liens.

	(b)  Immediately prior to the execution and delivery of the USA 
	Assignment, Clark USA had good and marketable title to each of the 
	Instruments free and clear of any Liens, including but not limited to 
	any Lien of UEC, and by executing and delivering the USA Assignment 
	Clark USA transferred to Assignor good and marketable title to each of 
	the Instruments free and clear of any Liens.

	SECTION 2.05.  Delivery of Crude Oil.  As of August 31, 1996, 1,452,000 
	barrels (in barrels of WTI) will have been delivered under the 
	Instruments at an average WTI Reference Price of $20.03 per barrel 
	(after deduction of the marketing fee of $0.25 per barrel) 

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	SECTION 2.06.  Reports and Information.  Attached hereto as Annex C are 
	true, correct and complete copies of all reports and notices furnished 
	to Assignor or Clark USA in connection with the Instruments.  The 
	Assignor has no reason to believe that such information is not accurate 
	in all material respects.

		     III. REPRESENTATIONS AND WARRANTIES OF ASSIGNEE

	As an inducement to Assignor and Clark USA to enter into this 
	Agreement, Assignee hereby represents and warrants to Assignor and Clark 
	USA as of the Effective Time on the Effective Date as follows (such 
	representations and warranties to survive for a period of six months 
	after the Effective Time on the Effective Date):

	SECTION 3.01.  Organization and Authority of Assignee.  Assignee is a 
	partnership duly organized, validly existing and in good standing under 
	the laws of the State of New York and has all necessary power and 
	authority to enter into this Agreement, to carry out its obligations 
	hereunder and to consummate the transactions contemplated hereby.  The 
	execution and delivery of this Agreement by Assignee, the performance 
	by Assignee of its obligations hereunder and the consummation by 
	Assignee of the transactions contemplated hereby have been duly 
	authorized by all requisite action on the part of Assignee.  This 
	Agreement has been duly executed and delivered by Assignee and 
	(assuming due authorization, execution and delivery by the other parties 
	hereto) this Agreement constitutes legal, valid and binding obligations 
	of Assignee, enforceable against Assignee in accordance with its terms.

	SECTION 3.02.  No Conflict.  The execution, delivery and performance of 
	this Agreement by Assignee do not and will not (a) violate, conflict 
	with or result in the breach of any provision of the partnership 
	agreement or organizational documents of Assignee or (b) conflict with 
	or violate any law or governmental order applicable to Assignee.

	SECTION 3.03.  Assignee Business.  Assignee is not, and is not an 
	affiliate of, one of the twenty (20) largest international oil 
	companies, as measured by revenue, as of the most recent calendar year 
	for which such information is available.

				     IV. MISCELLANEOUS

	SECTION 4.01.  Expenses.  Except as otherwise specified in this 
	Agreement, all costs and expenses, including, without limitation, fees 
	and disbursements of counsel, financial advisors and accountants, 
	incurred in connection with this 

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	Agreement and the transactions contemplated hereby shall be paid 
	by the party incurring such costs and expenses.

	SECTION 4.02.  Notices.  All notices, requests, claims, demands and 
	other communications hereunder shall be in writing and shall be given 
	or made (and shall be deemed to have been duly given or made upon 
	receipt) by delivery in person, by courier service, by facsimile, or 
	by registered or certified mail (postage prepaid, return receipt 
	requested) to the parties at the following addresses (or at such other 
	address for a party as shall be specified in a notice given in 
	accordance with this Section 4.02):

	(a)     if to Assignor:

		Clark Refining & Marketing, Inc.
		8182 Maryland Avenue
		St. Louis, Missouri  63105-3721
		Attn:           Maura Clark
		Facsimile:      (314) 854-1580

	(b)     If to Clark USA

		Clark USA, Inc.
		8182 Maryland Avenue
		St. Louis, Missouri  63105-3721
		Attn:           Maura Clark
		Facsimile:      (314) 854-1580

	(c)     if to Assignee:

		J. Aron & Company
		85 Broad Street
		New York, New York 10004
		Attn:           W. Thaddeus Miller
		Facsimile:      212-902-3876

	(d)     if to OPC:

		Occidental Petroleum Corporation
		10889 Wilshire Blvd.
		Los Angeles, California  90024
		Attn:           Treasurer
		Facsimile:      (310) 443-6661

	(e)     if to OCS:

		Occidental Crude Sales, Inc. (International)
		1200 Discovery Drive
		Bakersfield, California  93309-7008
		Attn:           Lynn T. Boulware,
		Director of Financial Services
		Facsimile:      (805) 321-6829
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	(f)     if to OCP:

		OXY USA, Inc.
		1200 Discovery Drive
		Bakersfield, California  93309-7008
		Attn:           Lynn T. Boulware,
		Director of Financial Services
		Facsimile:      (805) 321-6829

	SECTION 4.03.  Headings.  The descriptive headings contained in this 
	Agreement are for convenience of reference only and shall not affect 
	in any way the meaning or interpretation of this Agreement.

	SECTION 4.04.  Severability.  If any term or other provision of this 
	Agreement is invalid, illegal or incapable of being enforced by any 
	law or public policy, all other terms and provisions of this Agreement 
	shall nevertheless remain in full force and effect so long as the 
	economic or legal substance of the transactions contemplated hereby is 
	not affected in any manner materially adverse to any party.  Upon such 
	determination that any term or other provision is invalid, illegal or 
	incapable of being enforced, the parties hereto shall negotiate in good 
	faith to modify this Agreement so as to effect the original intent of 
	the parties as closely as possible in an acceptable manner in order 
	that the transactions contemplated hereby are consummated as originally 
	contemplated to the greatest extent  possible.

	SECTION 4.05.  Entire Agreement.  This Agreement constitutes the entire 
	agreement of the parties hereto with respect to the subject matter 
	hereof and supersedes all prior agreements and undertakings, both 
	written and oral, between the parties with respect to the subject 
	matter hereof.

	SECTION 4.06.  Assignment; Parties in Interest.  No party to this 
	Agreement (or any assignee of a party to this Agreement or any assignee 
	of such assignee) shall have the right to assign its rights and 
	obligations under this Agreement without the prior written consent of 
	each other party (which consent shall not be unreasonably withheld); 
	provided, however, that, without any consent of any other party to this 
	Agreement being necessary, (i) Assignee may assign all or any portion 
	of its rights and obligations under this Agreement to The Goldman Sachs 
	Group, L.P. (including any successor entity, "Group") or any company a 
	majority of the voting interests in which are owned or controlled by 
	Group and (ii) in connection with any securitization of this Agreement 
	(the "Securitization") Assignee and any Securitization vehicle shall 
	have the right to assign or otherwise transfer all or any portion of 
	its rights and obligations under this Agreement to any Securitization 
	vehicle that assumes such obligations.  This Agreement shall be binding 
	upon and inure solely to the benefit of the parties hereto (and any 
	Securitization vehicle or other proper assignee of the Assignee or any 
	Securitization vehicle in accordance with this Section 4.06), and 
	nothing in this Agreement, express or implied, is intended to or shall 
	confer upon any other person any right, benefit or remedy of any nature 
	whatsoever under or by reason of this Agreement provided that the 
	provisions of Section 1.01(b) and Section 3.03 shall also be for the 
	benefit of the other parties to the Instruments.  Each party to this 
	
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	Agreement acknowledges and agrees that the provisions of this Section 
	4.06 pertain only to assignments of the rights and obligations of the 
	parties under this Agreement and do not pertain, and have no effect on, 
	the right of the Assignee to assign or otherwise dispose of the 
	Instruments (it being understood that the right of the Assignee or any 
	successor to assign or otherwise dispose of the Instruments or any of 
	its rights or obligations thereunder shall be governed solely by the 
	terms of the Instruments).

	SECTION 4.07.  Governing Law.  This Agreement shall be governed by, and 
	construed in accordance with, the laws of the State of New York.  With 
	respect to any suit, action or proceedings relating to this Agreement, 
	each party irrevocably submits to the non-exclusive jurisdiction of the 
	courts of the State of New York and federal courts located in the 
	Borough of Manhattan in New York City and of the courts of the State of 
	Missouri and federal courts located in St. Louis.

	SECTION 4.08.  Contract Crude Oil.  OCP acknowledges that (i) the 
	provisions of Section 2.04 of the Purchase Contract (as defined in 
	Annex A) shall be of no force or effect, and (ii) it has no, and waives 
	any, right pursuant to Section 2.04 of the Purchase Contract to reduce 
	the number of Barrels of Contract Crude Oil (both as defined in such 
	Purchase Contract) it is obligated to deliver.

	SECTION 4.09.  Indemnification.  Each of the Assignor and the Assignee 
	agrees to indemnify the other from and hold it harmless against any and 
	all losses, damages, liabilities, claims and costs (including attorneys 
	fees) which the indemnified party may sustain by reason of any breach by 
	the indemnifying party of any of the representations, warranties and 
	agreements by the indemnifying party contained in this Agreement.  Each 
	of the Assignor and the Assignee acknowledges that its obligations under 
	this Section 4.09 shall survive any assignment of its rights and 
	obligations under this Agreement made in accordance with Section 4.06. 

	SECTION 4.10.  Further Assurances.  Each of Assignor, Clark USA, OPC, 
	OCS and OCP agrees to execute and deliver such additional documents, and 
	take such additional steps, as either Assignee or any proper transferee 
	from Assignee in accordance with Section 4.06 (including a 
	Securitization vehicle) may reasonably request in order to more fully 
	give effect to the 

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	sale, assignment, transfer and assumption provided 
	for in Article I and to assist in the consummation of the 
	Securitization, provided, however, that neither OPC, OCS or OCP shall 
	be required to execute and deliver any document or take any action if 
	the result thereof is to (i) cause such party to incur any expense which 
	is not reimbursed to it by Assignee or a proper transferee of Assignee 
	in accordance with Section 4.06 or (ii) subject OPC, OCS or OCP to 
	liability.  Each of OCP, OCS and OPC also acknowledges that Assignee 
	is planning a Securitization and will make a standard non-petition 
	covenant with respect to any bankruptcy remote Securitization vehicle 
	upon the request of one or more rating agencies.

	SECTION 4.11.  Interpretations.  (a)  It is Assignor's and Clark USA's 
	understanding that for purposes of Section 1 of the L/C Agreement (as 
	defined in Annex A), if an amount is drawn under the L/C (as defined in 
	Annex A), and it is determined (through arbitration, by agreement of the 
	parties or otherwise) that a portion of such draw was made for a purpose 
	permitted under the L/C Agreement (the "Permitted Amount") and that the 
	balance of such draw was not made for a purpose permitted under the L/C 
	Agreement (the "Impermissible Amount") , OPC (i) shall be required in 
	accordance with the terms of the L/C Agreement to cause the amount 
	available to be drawn under the L/C to be increased by an amount equal 
	to the Permitted Amount and (ii) shall be entitled to receive a refund 
	of an amount equal to the Impermissible Amount from the person that 
	drew it.

	(b)     It is Assignor's and Clark USA's understanding that all 
	references to "WTI (at Cushing, Oklahoma), as published in Platt's" in 
	the definition of "WTI Reference Price" in any of the Instruments refers 
	to the WTI price on line 1 in Platt's Oilgram Price Report.

	SECTION 4.12.  Miscellaneous.  (a) Each of OCS and OCP shall deliver to 
	Assignee  (with a copy to Assignor) (in each case in accordance with 
	Section 4.02) information (including, without limitation, monthly 
	statements) of the type and content that have been furnished to Clark 
	USA in connection with any of  the Instruments on a similar schedule.

	(b)     Assignor agrees to instruct OCS and OCP (i) to make all payments 
	that OCS is obligated to make pursuant to the Marketing Contract 
	(as defined in Annex A) in respect of Delivery Dates (as defined in the 
	Marketing Contract) on 
	
<PAGE> 9

	or after September 1, 1996 to Assignee and (ii) to replace Assignor with 
	Assignee in all oil contracts entered into pursuant to the Purchase 
	Contract and the Marketing Contract (both as defined in Annex A) after 
	the Effective Date. 

	SECTION 4.13.  Use of Proceeds   Assignor agrees to use and apply all 
	amounts received pursuant to Section 1.02 hereof in accordance with the 
	terms of each agreement binding on or affecting Assignor or Clark USA 
	or any of their respective assets, including, without limitation, the 
	following: (i) the Indenture dated as of September 15, 1992, as amended, 
	between Assignor and Nationsbank of Virginia, N.A., as Trustee, 
	relating to $175,000,000 9-1/2% Senior Notes due September 15, 2004; 
	(ii) the Indenture dated as of December 1, 1991, between Assignor and 
	Sovran Bank, NA., as Trustee, relating to $225,000,000 10-1/2% Senior 
	Notes due December 1, 2001; (iii) the Indenture dated as of May 15, 
	1993, as amended, between Clark USA and Bankers Trust Company, as 
	Trustee, relating to $264,000,000 Senior Secured Zero Coupon Notes due 
	2000; and (iv) the  Indenture dated as of December 1, 1995, between 
	Clark USA and The Chase Manhattan Bank, N.A., as Trustee, relating to 
	$175,000,000 Senior Notes due 2005.

<PAGE> 10
		     
	IN WITNESS WHEREOF, the parties have caused this Agreement to be 
	executed as of the date first written above by their respective officers 
	thereunto duly authorized.

					CLARK REFINING & MARKETING, INC.

					By:     /s/  M. J. Clark        
		 
					Name:   Maura J. Clark  

					Title:  Executive Vice President        
					& Chief Financial Officer       


					CLARK USA, INC.

					By:     /s/  M. J. Clark        

					Name:   Maura J. Clark  

					Title:  Executive Vice President        
					& Chief Financial Officer       


					J. ARON & COMPANY

					By:     /s/  Steven M. Schultz  

					Name:   Steven M. Schultz       

					Title:  Partner 
<PAGE> 11

As of the date first written above, the undersigned hereby consent to the terms 
hereof, and on their own behalf acknowledge and agree to the provisions of 
Sections 4.06, 4.08, 4.10 and 4.12(a).

					OCCIDENTAL PETROLEUM CORPORATION


					By:     /s/  John W. Alden      

					Name:   John W. Alden   

					Title:  Assistant Secretary and 
						Assistant Treasurer       


					OCCIDENTAL C.O.B. PARTNERS
					By OXY USA, Inc., its Managing Partner

					By:     /s/  John W. Alden      

					Name:   John  W. Alden  

					Title:  Assistant Secretary     


					OCCIDENTAL CRUDE SALES, INC. 
					(INTERNATIONAL)

					By:     /s/  Linda S. Peterson  

					Name:   Linda S. Peterson       

					Title:  Vice President and Secretary    

<PAGE> 12

Annex A

1.  Crude Oil Purchase Contract (the "Purchase Contract"), dated as of 
December 1, 1995, between Occidental C.O.B. Partners and Clark U.S.A., Inc. 

2.  Crude Oil Marketing Contract (the "Marketing Contract"), dated as of 
December 1, 1995, between Clark U.S.A., Inc. and Occidental Crude Sales, Inc.
(International) ("OCS").

3.  Guaranty, dated as of December 1, 1995 (the "Guaranty"), from Occidental 
Petroleum Corporation in favor of Clark U.S.A., Inc. of the obligations of 
OCP and OCS under the Purchase Contract and the Marketing Contract, 
respectively.

4.  Letter of Credit Agreement (the "L/C Agreement"), dated as of December 1, 
1995, between Clark U.S.A., Inc. and Occidental Petroleum Corporation.

5.  Designation Agreement, dated as of December 1, 1995, between Clark USA, 
Inc. and Occidental C.O.B. Partners.

6.  Irrevocable Letter of Credit No. LASB-226690 dated (the "L/C") November 
28, 1995, as amended, issued by the Bank of America National Trust and Savings 
Association in favor of Clark USA, Inc.