Ranger Oil (ROCC) 8-K Penn Virginia Corporation Completes Divestiture of

Exhibit 17.1

June 3, 2010

Mr. Robert Garrett

Chairman of the Board

Penn Virginia Corporation

Four Radnor Corporate Center

Suite 200

100 Matsonford Road

Radnor, PA 19087

Dear Rob:

It has been an honor to serve on the Penn Virginia Corporation Board of Directors over the last ten years. The company has made dramatic changes which I hope will achieve a very high level of success. At the pleasure of the board and in conjunction with Penn Virginia’s divestiture of Penn Virginia GP Holdings, I hereby resign from my position as a member of the Board of Directors of Penn Virginia Corporation effective immediately.

Very truly yours,

/S/ KEITH D. HORTON

Keith D. Horton

Cc: Nancy M. Snyder, Corporate Secretary Penn Virginia Corporation