Exhibit 99.1

            Cullen/Frost and Overton Bancshares Announce Merger Agreement

            SAN ANTONIO, Feb. 17 /PRNewswire/ -- Cullen/Frost Bankers, Inc.
(NYSE: CFR - news) and Overton Bancshares, Inc., announced today that they
have signed a definitive agreement that provides for the merger of Overton
into Cullen/Frost.

            The merger of Overton, the largest Fort Worth, Texas based banking
institution, will position Cullen/Frost in the attractive Tarrant and Dallas
counties. This entry into Fort Worth, the third largest job market in the state,
increases Cullen/Frost's deposit market share in the state from tenth to
seventh.

            Under the terms of the agreement, which was unanimously approved by
both boards of directors, Overton shareholders will receive 3.71 shares of
Cullen/Frost stock for each share of Overton common stock. The value of the
transaction is $253.5 million, which represents an exchange value of $215.85 per
Overton share based on Cullen/Frost's closing stock price of $58.1875 on
February 13, 1998. The merger, which will be accounted for as a
pooling-of- interests transaction, will be tax-free to Overton shareholders and
is expected to be consummated in the second quarter of 1998. The merger will
result in the issuance of approximately 4.36 million Cullen/Frost shares.

            Dick Evans, Chairman and CEO of Cullen/Frost said, "The combination
with Overton represents a logical extension of Cullen/Frost's Texas strategy and
provides us with an excellent entry vehicle into the attractive Fort
Worth/Dallas region. This combination enhances the overall Cullen/Frost
franchise and positions Cullen/Frost in each of the major high growth markets in
Texas. I am confident that Overton bankers and customers will feel at home with
Cullen/Frost because our community-oriented banking styles and customer bases
are so similar. The strong asset base and earnings power of the combined
franchise should result in improved returns for our shareholders. We are also
extremely pleased that David Tapp will continue his current responsibilities by
serving as the President of the Fort Worth/Dallas region."

            Dick Evans also noted that Cass Edwards, Chairman of the Board of
Overton Bancshares, Inc. and Denny Alexander, Chairman of the Board of Overton
Bank and Trust, have agreed to join the Cullen/Frost Board and all current
Overton board members will continue as advisory directors for their region.

            Denny Alexander said, "Overton has chosen a merger partner that will
generate superior long-term value for our stockholders. Our organizations have
highly complementary banking franchises with remarkably similar business and
operating cultures that will add value to our customers, employees and
stockholders. Working together we can bring our customers enhanced banking
services and a common commitment to quality customer service within the
communities we serve."

            The transaction is expected to be slightly dilutive to
Cullen/Frost's 1998 earnings per share and accretive thereafter. These
expectations are based on estimated cost savings of 15% of Overton's expense
base and revenue enhancements of 5% of Overton's revenue base. The synergies are
expected to be phased-in 50% in 1998, 75% in 1999 and 100% thereafter.

            Overton Bancshares, headquartered in Fort Worth, is an $863 million
bank holding company with 14 branches in Tarrant and Dallas counties. Overton
carries the sixth highest market share in the Fort Worth MSA where it operates
12 branches. Overton specializes in middle-market corporate lending and trust
services and has a fourteen-bank correspondent network and $1.8 billion in trust
assets under management.

            Cullen/Frost is a $5.2 billion bank holding company that provides
banking services through 60 financial centers across Texas in Austin, Corpus
Christi, Galveston, Houston, McAllen, New Braunfels, San Antonio, and San
Marcos. Cullen/Frost specializes in corporate, consumer and mortgage lending,
and trust management services. Cullen/Frost is the largest independent
Texas-based bank and its common stock is traded on the New York Stock Exchange
under the symbol CFR.

            CAUTIONARY STATEMENT CONCERNING FORWARD-LOOKING INFORMATION.

            This press release contains forward-looking statements with respect
to management beliefs, estimates, projections, assumptions, financial condition,
results of operation and business of Cullen/Frost, Overton, and, assuming the
consummation of the merger, a combined Cullen/Frost-Overton, including
statements relating to: (a) cost savings and accretion to reported earnings that
will be realized from the merger and (b) impact on the revenues of the merger.
These forward-looking statements involve certain risks and uncertainties,
including, among others, (a) potential difficulties in integrating Overton and
Cullen/Frost,(b) failure to achieve expected cost savings or revenue
enhancement, (c) competitive pressures and regulatory changes affecting
Overton's and Cullen/Frost's businesses, and (d) general economic factors,
including interest rate levels.