EXCLUSIVE TO THE WALL STREET JOURNAL

EMBARGOED UNTIL 11:00 PM CENTRAL, APRIL 6, 1997

MESA AND PARKER & PARSLEY PETROLEUM TO MERGE

CREATE PIONEER NATURAL RESOURCES COMPANY

A NEW LEADER IN ENERGY INDUSTRY

DALLAS, TEXAS AND MIDLAND, TEXAS, April 6, 1997-- MESA Inc. [NYSE: MXP] and
Parker & Parsley Petroleum Company [NYSE: PDP] today signed a definitive
agreement to merge and create Pioneer Natural Resources Company, the third
largest independent oil and gas exploration and production company in the
United States.

The merger combines MESA's well-known, long-lived, low cost natural
gas reserves and state-of-the-art gas processing facilities with Parker &
Parsley's long-lived, high quality oil reserves and exploration and
exploitation opportunities. The merger creates a new company with a balanced
oil and gas reserve base and significant production and reserve growth
potential. Pioneer will be led by a proven management team with the financial
strength and flexibility to pursue an aggressive growth strategy.

Following the planned merger, Pioneer will have critical mass,
stability and strength:

- - Pioneer's proved reserve base will be among the largest in the independent
oil and gas industry. Pioneer will have over 3.7 trillion cubic feet of
natural gas equivalent reserves, comprised of 1.9 trillion cubic feet of
natural gas and 293 million barrels of crude oil and liquids. Pioneer's
current daily production will be over 64,000 barrels of crude oil and
natural gas liquids and 459 million cubic feet of natural gas. Among the
"crown jewels" of the Pioneer holdings will be the Hugoton gas field in
Kansas and the Texas Panhandle and Spraberry fields in West Texas.

- - Pioneer's reserve base will be well balanced, with 52% natural gas and 48%
crude oil and liquids. Pioneer will be the only independent that owns both
long lived gas and long lived oil reserves and will have an aggregate
reserve life index in excess of 12 years. Pioneer's properties will provide
stable annual production and cash flow to fund accelerated development of
existing reserves, exploration for new reserves and strategic acquisitions.

- - Pioneer's enterprise value will be approximately $4.2 billion, based on
Friday's closing prices for the equity securities of each company and
including $1.3 billion in combined net debt outstanding. Combined, the
companies generated approximately $550 million in EBITDA in 1996 and have
significant borrowing capacity under their existing bank facilities.
Pioneer's debt will initially comprise 42% of its book capitalization. The
companies believe that this financial strength will allow greater access to
exploration, acquisition and financing opportunities, and allow the
companies to attract additional talented personnel.

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- - Pioneer's 1997 capital spending budget of $400 million, which excludes
recent and pending acquisitions, will be directed at increasing production
and reserves. Of this, Pioneer plans to invest $300 million on further
development of existing reserves. Approximately 600 wells will be drilled,
many with new technologies such as horizontal and dual lateral drilling.
Pioneer expects to invest approximately $100 million to explore for new
reserves using 3-D seismic evaluation technology and other proven methods.
In addition, the Company will continue to pursue strategic acquisitions.

- - Pioneer's management, directors and affiliates will own approximately 17%
of the Company's common stock upon consummation of the merger, strongly
aligning their interests with shareholders' interests. This is the highest
level of insider ownership among the top independent exploration and
production companies.

Pioneer's Chairman of the Board will be Jon Brumley, currently
Chairman and CEO of MESA. Mr. Brumley, 58, joined MESA in August 1996 and was
co-founder and Chairman of Cross Timbers Oil Co. and President and CEO of
Southland Royalty Co. Scott Sheffield, 44, currently Chairman and CEO of Parker
& Parsley, will be Pioneer's President and Chief Executive Officer. Mr.
Sheffield has been with Parker & Parsley since 1979. Pioneer will have fifteen
Directors on its board: the existing seven from MESA, seven from Parker &
Parsley, and one new director to be jointly named by the parties.

Mr. Brumley said, "MESA is paying a premium for a premium opportunity:
to create a major new independent with the size, strength and management
experience necessary to capitalize on the tremendous potential of MESA's long
lived natural gas reserves and Parker & Parsley's long lived oil properties.
This merger widens the door for both of our companies' management, technical,
operational and administrative teams to accelerate growth from a trot to a
gallop, stepping up our exploitation and exploration efforts across the board.
The timing is perfect for this combination, and we are seizing the day."

Mr. Sheffield commented, "This merger puts Pioneer in the top tier of
independent exploration and production companies in the country. Pioneer will
be the largest independent oil and gas company that has been built from
scratch, which is a tribute to the entrepreneurial spirit and culture of both
companies. With strong cash flow, a solid capital structure and a proven
management team, Pioneer will have more firepower to increase development and
exploration than either of us have on our own. We share a commitment to
operating efficiency and the use of cutting-edge technology to enhance the
productivity of our existing assets and to increase the success rate of our
exploration projects. As the third largest independent, we will be exposed to
more and better opportunities for exploitation, exploration and strategic
acquisitions, and we will have the financial flexibility necessary to
capitalize on those opportunities."

Richard Rainwater, currently a director of MESA and its largest
individual shareholder, said, "Pioneer will be aggressive under Jon Brumley and
Scott Sheffield, two of the country's most experienced and successful builders
of oil and gas companies. Pioneer will grow through well-planned development
and exploration and have the financial strength to act quickly and decisively
when new opportunities arise. The timing of this merger positions Pioneer to be
the

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preeminent independent producer of oil and gas at a time when the global supply
and demand environment should favor energy companies." Mr. Rainwater will be a
director, and the largest individual shareholder of Pioneer.

Pioneer Natural Resources Company will be headquartered in Irving,
Texas. Pioneer will retain Parker & Parsley's operations in Midland, Texas, and
the Company said that it expects that location's employment to increase in
coming years as Pioneer increases its production activities in the Permian
Basin. Pioneer will also have significant operations in Amarillo, Houston and
Corpus Christi, Texas; Oklahoma City, Oklahoma; and Lafayette, Louisiana.
Pioneer will have approximately 1,000 employees.

TERMS OF AGREEMENT

Under the merger agreement, holders of MESA and Parker & Parsley
common stock will receive common stock of Pioneer Natural Resources Company, a
newly-organized Delaware corporation. Parker & Parsley common stockholders will
receive one share of Pioneer common stock for each share of Parker & Parsley.
MESA's common stockholders will receive one share of Pioneer common stock for
every seven shares of MESA.

Holders of MESA Series A 8% Cumulative Convertible Preferred Stock and
Series B 8% Cumulative Convertible Preferred Stock will have the option to
receive either (i) 1.25 shares of Pioneer common for every seven shares held;
or (ii) one share of Pioneer Series A 8% Cumulative Convertible Preferred Stock
for every seven shares held; these shares are convertible into one share of
Pioneer common stock.

If a majority of the outstanding shares of MESA's Series A Preferred
Stock vote in favor of the merger, then all holders of MESA Series A Preferred
will receive common stock. This majority voting provision applies to MESA
Series B Preferred, however all of the holders of Series B Preferred have
agreed to vote in favor of the merger and exchange each of their shares for
common stock. Richard Rainwater and his affiliates own all of the outstanding
MESA Series B Preferred Stock.

The merger is subject to Parker & Parsley and MESA stockholder
approvals and Hart-Scott-Rodino approvals. If, during the fifteen trading days
ended five trading days before the shareholder votes, MESA's average closing
common stock price is less than $5 per share, each party will have the option
to terminate the merger agreement. The merger was unanimously approved by
Parker & Parsley's and MESA's boards of directors, and is expected to be
completed in July.

Except where otherwise noted, all amounts for Pioneer's capital
expenditures, cash flow, borrowing capacity, reserves and aggregate life are
provided herein on a combined basis, giving effect to the merger as of January
1, 1997, and pro forma for MESA's acquisition of Greenhill Petroleum
Corporation. EBITDA represents income from continuing operations plus interest
expense, income tax expense, exploration and abandonment charges, and
depletion, depreciation, and amortization expense.

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Merrill Lynch & Co. is serving as financial advisor to MESA and has
rendered its opinion to its board of directors with respect to the fairness,
from a financial point of view, of the merger consideration to MESA's common
stockholders, as well as the common stock conversion ratio applicable to MESA
preferred stock. Morgan Stanley & Co. Incorporated has rendered an opinion
with respect to the fairness of the common stock conversion ratio and preferred
stock conversion ratio to MESA's preferred stockholders. Goldman, Sachs & Co.
is serving as financial advisor to Parker & Parsley.

This announcement includes forward-looking statements within the
meaning of Section 27A of the Securities Act of 1933, as amended, and Section
21E of the Securities Exchange Act of 1934, as amended. Such forward-looking
statements include without limitation, estimates with respect to reserves,
production levels, cash flows, and capital expenditures. Although MESA and
Parker & Parsley believe that the expectations reflected in such
forward-looking statements are reasonable, they can give no assurance that such
expectations will prove to have been correct. Forward-looking statements are
qualified as may be provided in MESA's and Parker & Parsley's annual,
quarterly, and current reports and registration statements filed with the
Securities and Exchange Commission.

Attachments: Summary of Exchange Ratios
Fact Sheets on MESA and Parker & Parsley

# # #

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SUMMARY OF EXCHANGE RATIOS

FOR SHAREHOLDERS OF

MESA, INC. AND PARKER & PARSLEY PETROLEUM COMPANY

EXCHANGE RATIOS FOR COMMON SHAREHOLDERS:

Current Shareholding Receive Shares of Pioneer
- -------------------- -------------------------
7 common shares of MESA 1 common share of Pioneer

1 common share of Parker & Parsley 1 common share of Pioneer

EXCHANGE RATIOS FOR SERIES A PREFERRED SHAREHOLDERS:

MESA preferred shareholders may exchange their shares, at their option, as
follows:

Current Shareholding Receive Shares of Pioneer
- -------------------- -------------------------
7 shares MESA Series A 1.25 common shares of Pioneer
8% Cum. Cnv. Pfd.
or

1 Pioneer Series A
8% Cum. Cnv. Pfd.

If a majority of outstanding shareholders of MESA's Series A 8% Cum. Cnv. Pfd.
vote in favor of the merger, then ALL holders of such Series A will receive
common shares of Pioneer at the ratio described above.

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FACT SHEET - MESA, INC.

One of the largest independent oil and gas companies in the U.S., Mesa, Inc.
(NYSE: MXP) explores for and produces oil and gas. Mesa's reserves are
primarily concentrated in the Hugoton field in southwest Kansas and the West
Panhandle field in Texas. These fields are considered to be among the premier
natural gas properties in the U.S. and are characterized by long lived reserves
and stable, high margin production.

Mesa also has a significant and growing presence offshore in the Gulf of
Mexico, where it has been increasing its exploration efforts in recent years
through 3-D seismic evaluation technology.

Mesa owns and operates gas processing facilities in Satanta, Kansas and Fain,
Texas, where it extracts raw natural gas liquids and crude helium from its own
and third-parties' natural gas production.

Headquartered in Irving, Texas, Mesa has approximately 380 employees.

Mesa's strategy is to bring value to its shareholders by expanding its reserve
base, production and cash flows by:

- - PURSUING STRATEGIC ACQUISITIONS that offer opportunities for
exploitation and exploration, bring new core areas of operation and
increase Mesa's exposure to oil;

- - EXPANDING ITS EXPLORATION ACTIVITIES through increased investment in
higher risk projects that offer higher potential rates of return;

- - EXPLOITING ITS EXISTING AND ACQUIRED PROPERTIES AND maintaining
current production levels through investment in development drilling
projects as well as in existing production, compression and gathering
facilities, and technologies such as 3-D seismic evaluation;

- - EXPANDING ITS GAS PROCESSING BUSINESS to continue to extract the
processing margin on its own gas as well as to capture processing fees
from the processing it provides to third-parties;

- - MAINTAINING THE FINANCIAL FLEXIBILITY THAT allows it to act quickly
and decisively when investment opportunities arise.

RECENT EVENTS

- - In August 1996, Mesa completed a recapitalization led by Richard E.
Rainwater, which raised $265 million and allowed Mesa to repay and
refinance over $1.2 billion in debt and increase its cash flow for
investment in acquisitions and exploration.

- - On February 7, 1997, Mesa agreed to buy Greenhill Petroleum
Corporation for $270 million. The acquisition of the Greenhill
properties, which are concentrated in the inland waters of the
Louisiana Gulf Coast, the Texas Gulf Coast, offshore in the Gulf of
Mexico and in the Permian Basin, is the first phase of in Mesa's new
and significant exploitation and exploration drilling program.

- - On February 6, 1997, Mesa acquired all of MAPCO, Inc.'s condensate and
natural gas liquid ("NGL") interests in the West Panhandle field of
Texas for $66 million. Mesa expects this acquisition to result in an
additional 850,000 barrels in 1997 and approximately 11 million
barrels of proved reserves in 1997.
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MANAGEMENT

Members of Mesa's senior management include Jon Brumley, Chief Executive
Officer and Chairman of the Board of Directors, Dennis E. Fagerstone, Executive
Vice President and Chief Operating Officer, Stephen K. Gardner, Senior Vice
President and Chief Financial Officer, and M. Garrett Smith, Vice President -
Strategic Acquisitions.

Before joining Mesa in August 1996, Jon Brumley, 58, was co-founder and former
Chairman of Cross Timbers Oil Co. (NYSE: XTO). Prior to that, Mr. Brumley was
President and CEO of Southland Royalty Co. (NYSE: SRC).

MESA PROPERTIES WEST GULF OF
HUGOTON PANHANDLE MEXICO OTHER TOTAL
------------------------------------------------------------------------------

Proved reserves:
Natural gas (MMcf) 691,412 288,444 27,332 30,534 1,037,723
Natural gas liquids (MBbls) 45,418 42,498 120 15 88,051
Oil and condensate (MBbls) -- 3,971 2,188 704 6,863
Natural gas equivs (MMcfe) 963,920 567,258 41,180 34,848 1,607,206
Present value of
future net cash flows,
before income taxes,
discounted at 10% $ 1,129.7 $ 611.4 $ 67.6 $ 26.9 $ 1,835.6

FINANCIAL HIGHLIGHTS
(in thousands, except per share data)

YEARS ENDED DECEMBER 31,
1996 1996 1995
PRO FORMA* AS REPORTED
--------------------------------------------------

Revenues $ 382,355 $ 311,411 $ 234,959
Operating Income 104,934 96,688 47,965
Cash flow from operations -- 101,313 69,241
Net income (loss) before extraordinary item 32,498 8,339 (57,568)
Extraordinary loss on debt extinguishment -- (59,386) --
Net income (loss) -- (51,047) (57,568)
Net income (loss) per common share before 0.16 (.02) (.90)
extraordinary item
Loss per common share on extraordinary item -- (.92) --
Net income (loss) per common share -- (.94) (.90)
Total assets 1,494,527 1,213,879 1,486,824
Long-term debt, including current maturities 1,073,272 808,077 1,236,743

*Pro forma (unaudited) for the 1996 recapitalization and the acquisition of
Greenhill Petroleum Corporation
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FACT SHEET - PARKER & PARSLEY PETROLEUM COMPANY

Parker & Parsley Petroleum Company (NYSE: PDP) is among the largest independent
oil and gas exploration and production companies in the United States. The
company has total proved reserves of more than 302 million barrel oil
equivalents (MMBOE), 54 percent crude oil. Parker & Parsley's domestic oil and
gas drilling and production operations are concentrated in Texas, Oklahoma,
Louisiana, and New Mexico, with international drilling and production
operations in Argentina.

Over the past three years, the company has added over 285 MMBOE of total proved
oil and gas reserves through a balanced strategy of acquisition, development
and exploration. Parker & Parsley has achieved this growth at an average cost
of $3.99 per BOE, significantly below the industry average. In addition, the
company has replaced 377 percent of its annual production volumes with new
reserve additions.

Headquartered in Midland, Texas, Parker & Parsley has offices in Midland and
Corpus Christi, Texas; Oklahoma City, Oklahoma; and Buenos Aires, Argentina.
The company employs approximately 650 persons.

STRATEGY

Parker & Parsley Petroleum is focused on being the industry leader in applying
the latest technology and implementing the best production practices to achieve
the maximum value for its shareholders. During 1996, the company adhered to a
focused growth strategy, balancing backyard development projects with a
moderate yet high potential exploration program.

1996 EVENTS

- - Added 75 million barrel oil equivalents (BOES) of proved reserves at a
finding cost of $3.10 per BOE. Three-year finding costs averaged
$3.99 per BOE.

- - Replaced 314% of oil and gas production. Replaced 377% of production
over the last three years.

- - Increased oil and gas production 13%, excluding production from
properties divested.

- - Sold Australasian properties for $238 million recognizing an $83
million gain.

- - Added new reserve potential with War Wink oil discovery and
identification of 13 additional exploration prospects in the Delaware
Basin of West Texas.
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MANAGEMENT

Parker & Parsley is managed by Scott D. Sheffield, Chairman of the Board,
President, and Chief Executive Officer; Timothy A. Leach, Executive Vice
President; Steven L. Beal, Senior Vice President, Chief Financial Officer and
Treasurer; Timothy L. Dove, Senior Vice President, Business Development; and
Lon C. Kile, Senior Vice President and investor contact.

Scott Sheffield has been President and a director of Parker & Parsley since May
1990, and Chairman of the Board and Chief Executive Officer since October 1990.
Mr. Sheffield joined Parker & Parsley Development Company (PPDC), the
predecessor company, as a petroleum engineer in 1979, and served as Vice
President-Engineering of PPDC from September 1981 to April 1985, when he was
elected President and a director. In March 1989, Mr. Sheffield was elected
Chairman of the Board and Chief Executive Officer of PPDC. Previously, Mr.
Sheffield was a production and reservoir engineer for Amoco Production Company.

PARKER & PARSLEY PETROLEUM - OIL AND GAS RESERVE PROFILE

DIVISION MMBBLS BCF MMBOE %
-------------------------------------------

Spraberry 112.3 284.6 159.7 53%
Permian Basin 41.4 119.7 61.4 20%
Gulf Coast 4.3 252.3 46.4 16%
Mid Continent 2.8 167.1 30.6 10%
Other 3.1 5.7 4.1 1%
-------------------------------------------
Total 163.9 829.4 302.2 100%

BBL = Standard barrel of 42 U.S. gallons, basic unit for measuring production
of crude oil and condensate
MMBBLS = Millions of barrels
BCF = One billion cubic feet
BOE = Barrel-of-oil-equivalent, used in the U.S. to express oil and gas volumes
on a comparable basis
MMBOE = Millions of Barrel of oil equivalents

FINANCIAL HIGHLIGHTS
(in millions, except per share data)

YEARS ENDED DECEMBER 31,
1996 1995 1994

Revenues $ 535.3 $ 513.7 $ 496.2
Net income (loss) 140.2 (99.8) (14.6)
Cash flow from operations 230.1 157.3 129.8
Net income (loss) per common share 3.92 (2.83) (.49)
Total assets 1,199.9 1,319.2 1,604.9
Long-term debt, less current maturities 320.9 586.5 708.8