<PAGE>
 

                                 EXHIBIT INDEX
 

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<CAPTION>
 NUMBER                                  EXHIBIT
 ------                                  -------
 <C>     <S>
  3(a)*  --Restated Certificate of Incorporation of Zapata filed with Secretary
          of State of Delaware May 3, 1994 (Exhibit 3(a) to Current Report on
          Form 8-K dated April 27, 1994 (File No. 1-4219)).
  3(b)*  --Certificate of Designation, Preferences and Rights of $1 Preference
          Stock (Exhibit 3(c) to Zapata's Quarterly Report on Form 10-Q for the
          fiscal quarter ended March 31, 1993 (File No. 1-4219)).
  3(c)*  --Certificate of Designation, Preferences and Rights of $100
          Preference Stock (Exhibit 3(d) to Zapata's Quarterly Report on Form
          10-Q for the fiscal quarter ended March 31, 1993 (File No.
          1-4219)).
  3(d)*  --By-laws of Zapata, as amended effective August 17, 1994.
  4(a)*  --Second Amended and Restated Master Restructuring Agreement, dated as
          of April 16, 1993 between Zapata and Norex Drilling Ltd. (Exhibit 12
          to Zapata's Amendment No. 3 to Schedule 13D dated April 30, 1993).
  4(b)*  --First Amendment to Second Amended and Restated Master Restructuring
          Agreement dated as of May 17, 1993 between Zapata and Norex Drilling
          Ltd. (Exhibit 4(c) to Zapata's Registration Statement on Form S-1
          (No. 33-68034)).
  4(c)*  --Second Amendment to Second Amended and Restated Master Restructuring
          Agreement, dated as of December 17, 1993 between Zapata and Norex
          Drilling Ltd. (Exhibit 4(c) to Zapata's Annual Report on Form 10-K
          for the fiscal year ended September 30, 1993 (File No. 1-4219)).
  4(d)*  --Securities Liquidity Agreement, dated as of December 19, 1990, by
          and among Zapata and each of the securities holders parties thereto
          (Exhibit 4(b) to Zapata's Annual Report on Form 10-K for the fiscal
          year ended September 30, 1990 (File No. 1-4219)).
  4(e)*  --Consent Letter and Waiver dated as of March 7, 1995 by and between
          Norex America, Inc. and Zapata Corporation. (Exhibit 4(e) to Zapata's
          Quarterly Report on Form 10-Q for the quarter ended March 31, 1995
          (File No. 1-4219)).
 10(a)** --Letter Agreement dated June 29, 1995 by and between Enterra
          Corporation and Zapata Corporation.
 10(b)** --Assignment and Assumption of Consulting Agreement effective as of
          July 1, 1995 by and between Zapata Corporation and Zapata Protein,
          Inc.
 27      --Financial Data Schedule.
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 * Incorporated by reference to the Zapata Corporation Annual Report on Form
   10-K for the fiscal year ended September 30, 1994.
**Filed with Form 10-Q for quarter ended June 30, 1995.
 
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