Document:

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                                                                   Exhibit 10.11

                TRANSACTION CONFIRMATION DATED DECEMBER 14, 2004
           BETWEEN ATLAS AMERICA, INC. AND UGI ENERGY SERVICES, INC.
                                 D/B/A/ GASMARK

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                                                              Revised EXHIBIT A

                            TRANSACTION CONFIRMATION
                             FOR IMMEDIATE DELIVERY

             Atlas America, Inc.                      Date: December 14, 2004
                                                      Transaction Confirmation
                                                      #: ___________

This Transaction Confirmation is subject to the Base Contract between Seller
and Buyer dated November 13, 2002. The terms of this Transaction Confirmation
are binding unless disputed in writing within 2 Business Days of receipt
unless otherwise specified in the Base Contract.

SELLER:                                 BUYER:

Atlas America, Inc.                     UGI Energy Services,
311 Rouser Corp.                        Inc. d/b/a GASMARK
Moon Two, PA 15108                      1100 Berkshire
Attn: Michael Brecko                    Blvd., Suite 305
Phone: 412-262-2830x126                 Wyomissing, PA 19610
Fax: 412-262-3927                       Attn: Robert Meder
Base Contract No.                       Phone: 610-373-7989
Transporter:                            Fax: 610-374-4288
Transporter Contract Number:            Base Contract No.
                                        Transporter:
                                        Transporter Contract Number:

Contract Price $________ /MMBtu or NYMEX LDS plus $.75 payable on Adjusted Mcfs.

Delivery Period: Begin: June 1, 2005                       End: March 31, 2007

Performance Obligation and Contract Quantity: (Select One)

Firm (Fixed Quantity):   Firm (Variable Quantity)      Interruptible:
________ MMBtus/day      2,500 MMBtus/day              Up to ________ MMBtus/day
|_| EFP                  subject to Section 4.2
                         at election of
                         |_| Buyer or |_| Seller

Delivery Point(s):  Various meters located on Dominion East Ohio's pipeline
system
(If a pooling point is used, list a specific geographic and pipeline
location):

Special Conditions:  Additional walls may be added upon mutual consent of the
parties.  All gas produced under this agreement shall be produced from wells
located within the state of Ohio.  Atlas America shall have trigger rights to
lock in prices.  Adjusted Mcfs are the actual Mcfs at the meter converted to
MMBtu's using a conversion factor of 1.109 to get total MMBtu's. The total
MMBtu's are converted to Adjusted Mcfs by dividing the MMBtu's by a factor of
1.036. These conversion factors are set by Dominion East Ohio and are subject
to change by Dominion East Ohio.

Atlas America has chosen to lock in prices on the volumes produced each month
as per the attached "Confirmation of Price Locks".

All volumes sold in excess of the locked in volumes shall continue to be
priced as per the pricing clause above.

Seller: Atlas America, Inc.             Buyer: UGI Energy Services,
                                               Inc., d/b/a GASMARK

By:____________________________________ By:____________________________________

Title:_________________________________ Title: Vice President,
                                               Gas Supply & Risk Management

Date:__________________________________ Date:__________________________________

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Copyright (C) 2002 North American
Energy Standards Board, Inc.                                NAESB Standard 6.3.1
All Rights Reserved                Page 1 of 10                   April 19, 2002

<PAGE>

                                                              Revised EXHIBIT A

                            TRANSACTION CONFIRMATION
                             FOR IMMEDIATE DELIVERY

             Atlas America, Inc.                      Date: December 14, 2004
                                                      Transaction Confirmation
                                                      #: ___________

This Transaction Confirmation is subject to the Base Contract between Seller
and Buyer dated November 13, 2002. The terms of this Transaction Confirmation
are binding unless disputed in writing within 2 Business Days of receipt
unless otherwise specified in the Base Contract.

SELLER:                                 BUYER:

Atlas America, Inc.                     UGI Energy Services,
311 Rouser Corp.                        Inc. d/b/a GASMARK
Moon Two, PA 15108                      1100 Berkshire Blvd., Suite 305
Attn: Michael Brecko                    Wyomissing, PA 19610
Phone: 412-262-2830x126                 Attn: Robert Meder
Fax: 412-262-3927                       Phone: 610-373-7999
Base Contract No.                       Fax: 610-374-4288
Transporter:                            Base Contract No.
Transporter Contract Number:            Transporter:
                                        Transporter Contract Number:

Contract Price $________ /MMBtu or NYMEX LDS plus $.385 per Dth

Delivery Period: Begin: April 1, 2006                      End: March 31, 2007

Performance Obligation and Contract Quantity: (Select One)

Firm (Fixed Quantity):   Firm (Variable Quantity)      Interruptible:
________ MMBtus/day      20,000 MMBtus/day             Up to ________ MMBtus/day
|_| EFP                  subject to Section 4.2
                         at election of
                         |_| Buyer or |_| Seller

Delivery Point(s):  Texas Eastern Meter Number 73133, Station Name of Prah and
the Joseph Meter in Market area M2
(If a pooling point is used, list a specific geographic and pipeline
location):

Special Conditions:  Additional wells may be added upon mutual consent of the
parties.  All gas produced under this agreement shall be produced from wells
located within the Commonwealth of Pennsylvania. Atlas America shall have
trigger rights to lock in prices.

Atlas America has chosen to lock in prices on the volumes produced each month
as per the attached "Confirmation of Price Locks".

All volumes sold in excess of any locked in volumes shall continue to be
priced as per the pricing clause above.

Seller: Atlas America, Inc.             Buyer: UGI Energy Services,
                                               Inc.,d/b/a GASMARK

By:____________________________________ By:____________________________________

Title:_________________________________ Title: Vice President,
                                               Gas Supply & Risk Management

Date:__________________________________ Date:__________________________________

-------------------------------------------------------------------------------

Copyright (C) 2002 North American
Energy Standards Board, Inc.                               NAESB Standard 6.3.1
All Rights Reserved                 Page 1 of 10                  April 19, 2002<PAGE>

                                                                   EXHIBIT 10.12
                                                                   -------------

                   GUARANTY DATED JANUARY 1, 2005 BETWEEN UGI
                     CORPORATION AND VIKING RESOURCES CORP.

<PAGE>

                                    GUARANTY

        This Guaranty (the "Guaranty") is made by UGI Corporation ("Guarantor"),
a Pennsylvania corporation, effective as of January 1, 2005 (the "Effective
Date"), in favour of Viking Resources Corp. ("Creditor"), a Pennsylvania
corporation.

        WHEREAS, UGI Energy Services, Inc. d/b/a GASMARK ("Debtor"), a
Pennsylvania corporation and Creditor are parties to various agreements for the
purchase, sale and/or transportation of natural gas (whether one or more, the
"Agreement"); and

        WHEREAS, the execution and delivery of this Guaranty is a condition to
Creditor's further performance of its obligations under the terms of the
Agreement and Guarantor has agreed to provide assurance for the performance of
Debtor's obligations in connection with the Agreement.

        NOW, THEREFORE, in consideration of the premises and other good and
valuable consideration, the adequacy, receipt and sufficiency of which are
hereby acknowledged, Guarantor hereby agrees as follows:

1.  GUARANTY. Guarantor hereby unconditionally and absolutely guarantees the
    punctual payment when due of Debtor's payment obligations arising under the
    Agreement, as may be amended or modified from time to time, together with
    any interest thereon (collectively, the "Guaranteed Obligations"); provided,
    however, that the total liability of Guarantor hereunder, regardless of any
    amendment or modification to the Agreement, is limited to the lesser of (a)
    all amounts owed by Debtor to Creditor under the Agreement or Seven Million
    Dollars or ($7,000,000.00). Guarantor's obligations and liability under this
    Guaranty shall be limited to payment obligations of Debtor and Guarantor
    shall have no obligation to sell, deliver, supply or transport gas and/or
    electricity.

2.  WAIVER. This is a guaranty of payment and not of collection. Guarantor
    hereby waives:

        (a) notice of acceptance of this Guaranty, of the creation or existence
            of any of the Guaranteed Obligations and of any action by Creditor
            in reliance hereon or in connection herewith; and

        (b) any requirement that suit be brought against, or any other action by
            Creditor be taken against, or any notice default or other notice be
            given to, or any demand be made on, Debtor or any other person, or
            that any other action be taken or not taken as a condition to
            Guarantor's liability for the Guaranteed Obligations or as a
            condition to the enforcement of this Guaranty against Guarantor,
            except as expressly defined herein.

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3.  TERM: TERMINATION. This Guaranty shall continue in full force and effect for
    a term commencing on the Effective Date and continuing until March 31, 2007.
    Notwithstanding the foregoing, this Guaranty may be terminated at any time
    by the Guarantor by providing at least forty-five (45) days prior written
    notice to Creditor; provided, however, upon termination hereof, Guarantor
    agrees that the obligations and liabilities hereunder shall continue in full
    force and effect with respect to any obligations incurred prior to the
    termination date, plus any interest thereon, and any fees and costs of
    enforcement in connection herewith.

    This Guaranty shall continue to be effective or be reinstated, as the case
    may be, if at any time any payment of any of the Guaranteed Obligations are
    annulled, set aside, invalidated, declared to be fraudulent or preferential,
    rescinded or must otherwise be returned, refunded or repaid by Creditor upon
    the insolvency, bankruptcy, dissolution, liquidation or reorganization of
    Debtor or any other guarantor, or upon or as a result of the appointment of
    a receiver, intervenor or conservator of, or trustee or similar officer for,
    Debtor or any other guarantor or Any substantial part of its property or
    otherwise, all as though such payment or payments had not been made.

4.  DEMAND. Prior to commencing any legal proceeding to enforce this Guaranty,
    the Creditor shall provide the Guarantor with written demand ("Demand")
    setting forth Debtors obligation and providing the Guarantor or the Debtor
    three (3) business days in which to satisfy the obligation and thereby avoid
    enforcement of the Guaranty. Any Demand by Creditor hereunder shall be in
    writing, signed by a duly authorized officer of Creditor and delivered to
    the Guarantor pursuant to Section 4 hereof, and shall (a) reference this
    Guaranty, (b) specifically identify the Debtor, the Guaranteed Obligations
    to be paid and the amount of such Guaranteed Obligations and (c) set forth
    payment instructions. Guarantor shall pay, or cause to be paid, such
    Guaranteed Obligations within three (3) business days of receipt of such
    Demand.

    These are no conditions precedent to the enforcement of this Guaranty,
    except as set forth above. It shall not be necessary for Creditor, in order
    to enforce payment by Guarantor under this Guaranty, to show any proof of
    Debtor's default, to exhaust its remedies against Debtor, any other
    guarantor, or any other person liable for the payment or performance of the
    Guaranteed Obligations. Creditor shall not be required to mitigate damages
    to take any other action to reduce, collect, or enforce the Guaranteed
    Obligations.

5.  SUBROGATION. Guarantor shall be subrogated to all rights of Creditor against
    Debtor in respect of any amounts paid by Guarantor pursuant to the Guaranty,
    provided that Guarantor waives any rights it may acquire by way of
    subrogation under this Guaranty, by any payment made hereunder or otherwise,
    until all of the Guaranteed Obligations shall have been irrevocably paid to
    Creditor in full. If any amount shall be paid to the Guarantor on account of
    such subrogation rights at any time when all the Guaranteed Obligations
    shall not have been paid in full, such amount shall be held

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    in trust for the benefit of Creditor and shall forthwith be paid to Creditor
    to be applied to the Guaranteed Obligations.

6.  NOTICES. All demands, notices and other communications provided for
    hereunder shall, unless otherwise specifically provided herein, (a) be in
    writing addressed to the party receiving the notice at the address set forth
    below or at such other address as may be designated by written notice, from
    time to time, to the other party, and (b) be effective upon delivery, when
    mailed by U.S. mail, registered or certified, return receipt requested,
    postage prepaid, or personally delivered. Notice shall be sent to the
    following addresses:

        IF TO CREDITOR:

        Atlas America, Inc.
        Attention: Michael Brecko
        311 Rouser Road
        P.O. Box 611
        Moon Township, PA 15108

        IF TO GUARANTOR:

        UGI Corporation
        Attention: Robert Krick, Treasurer
        P.O. Box 858
        Valley Forge, PA 19482

7.  NO WAIVER: REMEDIES. Except as to applicable statutes to limitation, no
    failure on the part of Creditor to exercise, and no delay in exercising, any
    right hereunder shall operate as a waiver thereof, nor shall any single or
    partial exercise of any right hereunder preclude any other or further
    exercise thereof or the exercise of any other right. The remedies herein
    provided are cumulative and not exclusive of any remedies provided by law.

8.  ASSIGNMENT: SUCCESSORS AND ASSIGNS. Creditor may, upon notice to Guarantor,
    assign its rights hereunder without the consent of Guarantor. Guarantor may
    assign its rights hereunder with the prior written consent of Creditor,
    which consent shall not be unreasonably withheld. Subject to the foregoing,
    this Guaranty shall be binding upon and inure to the benefit of the parties
    hereto and their respective successors, permitted assigns, and legal
    representatives.

9.  GOVERNING LAW: SUBMISSION TO JURISDICTION. THIS GUARANTY SHALL BE GOVERNED
    BY, AND CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE COMMONWEALTH OF
    PENNSYLVANIA AND APPLICABLE FEDERAL LAW.

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10. ENTIRE AGREEMENT. This Guarantee sets forth the entire understanding and
    agreement between the parties as to matters covered herein and expressly
    supersedes all prior guarantees, agreements and understandings between the
    parties with respect to the subject matter hereof. Any change, modification,
    amendment, or alteration of this Guaranty shall be in writing and no course
    of dealing between the Parties prior or subsequent to the date of this
    Guaranty shall be construed to change, modify, amend, alter or waive the
    terms hereof.

IN WITNESS WHEREOF, UGI Corporation has caused this Guaranty to be duly executed
and delivered by its duly authorized officer effective as of the Effective Date
first written above.

UGI CORPORATION

By:     /s/ Robert W. Krick
   ---------------------------
Name:   Robert W. Krick
Title:  Treasurer

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