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Exhibit 10.11



                                                                  August 1, 2007



PANTERRA RESOURCE CORP.                              ENDEAVOR ENERGY CORP.
260, 603 - 7th Avenue S.W.                           1110, 521 - 3 Avenue SW
Calgary, AB                                          Calgary, AB
T2P 2T5                                              T2P 3T3

Attention: Fred Rumak                                Attention: Keith Miles



STEALTH VENTURES LTD.                                RANCHMANS RESOURCES LTD.
705, 777 - 5 Avenue SW                               850, 808 - 4 Avenue SW
Calgary, AB                                          Calgary, AB
T2P 3R5                                              T2P 3E8


Attention: Rob Bell                                  Attention: Mike Logan





RE:   SEISMIC OPTION LETTER OF INTENT
      SOUTH SASKATCHEWAN


Further  to  our  recent  conversation,  Endeavor  Energy  Corp.  and  Ranchmans
Resources Ltd. (hereinafter collectively referred to as "Optionee") are prepared
to enter into a Seismic Option with PanTerra Resource Corp. and Stealth Ventures
Ltd. (hereinafter  referred to as "Optioner");  the following sets out the terms
and conditions:

1.       Definitions
         -----------

         Each capitalized term used in this Head Agreement will have the meaning
         given to it in the Farmout & Royalty Procedure, and, in addition:

         (a)  "Contract  Depth" means  sufficient  depth to Option any formation
         below  the top of the  Viking  that may be  prospective  following  the
         shooting of the program described in Clause 3.

         (b) "Option Lands" means the lands described in Schedule "B".




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<PAGE>

2.       Schedules
         ---------

         The  following  Schedules  are  attached  hereto  and made part of this
         Agreement:

         (a) Schedule "A", which is the Farmout & Royalty Procedure elections;
         (b) Schedule "B", which is the Options Lands;
         (c) Schedule "C", which is the Operating Procedure;
         (d) Schedule "D",  which  specifies  the types of drilling  information
         required to be supplied by the Optionee to the Optioner pursuant to the
         Farmout & Royalty Procedure.

3.       Seismic Option
         --------------

         The Optionee  shall shoot a minimum of a  $500,000.00  seismic  program
         ("Seismic Program") with the tail spreads not exceeding one mile of the
         Option Lands prior to December 15, 2007.

         Prior to January 15, 2008 Optionee shall elect to either:

         (a) Commit to shoot a  $500,000.00  seismic  program  ("Second  Seismic
         Program")  on or within one mile of the Option  Lands within 60 days of
         its election to shoot or prior to April 30, 2008; or

         (b) Commit to drill an Option  Well at a location  of its choice on the
         Option  Lands.  The Option Well shall be spudded  within 60 days of its
         election to drill and drilled to Contract Depth and  completed,  capped
         or abandoned; or

         (c) Terminate the Option.

         (d) The Optionee  must drill a well within 1 year of the first  earning
         well or terminate the option.

         Should Optionee elect option (a) of this Letter of Intent,  on or prior
         to July 31, 2008 Optionee shall elect to:

         (a) Commit to drill an Option  Well at a location  of its choice on the
         Option  Lands.  The Option Well shall be spudded  within 90 days of its
         election to drill and drilled to Contract Depth and competed, capped or
         abandoned; or

         (b) Terminate the Option.

4.       Option Well Earning
         -------------------

         Subject  to  compliance  with  Article  3.00 of the  Farmout  & Royalty
         Procedure,  Optionee will earn 100% of the Optionor's Working Interest,
         subject  to the  Overriding  Royalty,  in the  lands  earned  from  the
         applicable  Permit  ("Option  Well Earning  Block"),  use  calculations
         pursuant to the earning  provisions under the  Saskatchewan  Government
         PNG License Regulations.

         Optionor shall have the right to participate with the Optionee,  in the
         drilling  of any  Option  Well on the  Option  Lands  for  20%  working


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         interest.  In the event Optionor  participates  in the Option Well, the
         Overriding  Royalty shall be calculated on the  Optionee's  80% working
         interest in such Option Well Earning Block.

         Optionee  shall earn Viking  rights on all option lands after  drilling
         its first earning well.

         Prior to  earning  by  Optionee,  if  Optionor  discovers  Viking  gas,
         Optionor  shall retain the drilling  spacing unit,  plus one additional
         section of its choice.

5.       Additional Seismic Programs and Option Wells
         --------------------------------------------

         If the  Optionee  has drilled the Option Well to Contract  Depth and is
         not otherwise in default,  the Optionee will have continuing options to
         shoot  additional  seismic  programs to continue the option to drill as
         per Clause  3.(a) or drill  additional  Option  Wells on the  remaining
         Option  Lands to earn an interest in the  unearned  Option  Lands.  The
         Optionee  may elect,  by notice to the  Optionor  within 90 days of the
         drilling rig release date of the previous  Option Well, to either shoot
         a $500,000.00 seismic program ("Additional Seismic Program") or drill a
         further  Option Well  ("Additional  Option  Well").  If the Optionee so
         elects,  the Optionee must spud such  Additional  Option Well within 90
         days of that  election.  The terms and  conditions  with respect to the
         Option  Well shall apply  mutatis  mutandis  to the  Additional  Option
         Wells.

         Optionor  shall be  provided a show and tell and a copy of  interpreted
         data in the event of participation by Optionor.

6.       Abandonment
         -----------

         The  parties  hereby  acknowledge  and agree that  Article  7.00 of the
         Farmout and Royalty  Procedure  which is entitled  Abandonment of Wells
         has been  amended to allow the  Optionor  to take over an Option  well.
         Should  Optionor  elect to take over an  Option  Well,  Optionee  shall
         assign the Option Well along with the applicable  surface  rights.  All
         responsibilities,  obligations  and  liabilities  associated  with  the
         Option  Well  after  Optionor  takes  over the well  shall lie with the
         Optionor.

7.       Reasonable Extension
         --------------------

         In the event the  Optionee  has  committed  to drill the Option Well as
         outlined   in  Clause  3  hereof  and   either  or  both   governmental
         restrictions and ground conditions make the drill site inaccessible and
         precludes  the Optionee  from spudding the Option Well on or before the
         date provided in Clause 3, Optionor  shall grant Optionee the extension
         or  extensions  required  to Spud the  Option  Well  until such time as
         either or both  governmental  restrictions and ground conditions permit
         Optionee  to access the  Option  Well  drill  site  together  with such
         reasonable  additional  time as may be necessary to permit  Optionee to
         organize and effect the Spudding thereof.

8.       Restriction On Additional Drilling During Earning Phase
         -------------------------------------------------------
         No Party may propose the drilling of an  additional  well on the Option
         Lands  earned as a result of the drilling of an Earning Well until such
         time as the  Optionee has earned an interest in all of the Option Lands
         or the Optionee's right to earn that interest has terminated.

         This clause shall not restrict Optionor from drilling shallow wells.


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9.       Operating Procedure
         -------------------

         Endeavor Energy Corp. will be the initial  Operator under the Operating
         Procedure.

10.      Rentals
         -------

         Rentals shall be charged on a 50/50 basis, 1 year from the date of this
         agreement on all lands held under the agreement.

11.      Land Sale
         ---------
         Any lands purchased by Optionor shall be included in this agreement.

         Thereafter,  any party  acquiring  lands  within two miles of any lands
         hereunder,   such  party  shall  notify  the  remaining  party  of  the
         acquisition,  and shall offer that party the respective deep or shallow
         rights for 20% of the consideration expenditures.

         In the event the foregoing terms and conditions  herein are acceptable,
         please   indicate  your   concurrence  by  signing  and  returning  the
         counterpart  execution  page of this  Agreement to the attention of the
         undersigned.  This  offer  is  open  for  acceptance  until  4:30  p.m.
         Wednesday,  August 1, 2007 and Optionee  will  thereupon  prepare final
         agreement incorporating, inter alia, the terms set out herein.

     Yours truly,



     ENDEAVOR ENERGY CORP.



     Keith Miles



     jm/attachments



     Agreed to this 1st day of August, 2007.



     /s/  Fred Rumak
     -----------------------------------------------

     PANTERRA RESOURCES CORP.


     Agreed to this 1st day of August, 2007.



     /s/ Keith Miles
     -----------------------------------------------

     ENDEAVOR ENERGY CORP.




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     Agreed to this 1st day of August, 2007.



     /s/ Rob bell
     -----------------------------------------------

     STEALTH VENTURES LTD.





     Agreed to this 1st day of August, 2007.



     /s/ Mike Logan
     -----------------------------------------------

     RANCHMANS RESOURCES LTD.


This is a counterpart execution page attached to and forming a part of a Seismic
Option  Letter of Intent  dated  August 1, 2007  among  Endeavor  Energy  Corp.,
Ranchmans  Resources Ltd.,  Stealth Ventures Ltd., and PanTerra Resource Corp. -
South Saskatchewan







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                                   SHEDULE "A"

Schedule "A" attached to and forming a part of a Seismic Option Letter of Intent
dated August 1, 2007 among  Endeavor  Energy Corp.,  Ranchmans  Resources  Ltd.,
Stealth Ventures Ltd., and PanTerra Resources Corp. - South Saskatchewan


              Farmout & Royalty Procedure Elections and Amendments

1.       Effective Date (Sub clause 1.01 (f)) - August 1, 2008

2.       Payout (Sub clause 1.01 (t), if Article  6.00  applies) - Alternate A -
         _____, Alternate B ______, Alternate B options, if applicable - _____m3
         Equivalent Production and _____ years.

3.       Incorporation   of   Clauses   From  1990  CAPL   Operating   Procedure
         (Clause 1.02)

(i)      Insurance (311)       Alternate A - _______,   Alternate B -
         ____X_____ ,

(ii)     Address for Notices (Clause 2202) -

                     The Parties' addresses for service are:

                  PanTerra Resource Corp.
                  260, 603 - 7 Avenue SW
                  Calgary, AB T2P 2T5
                  Attention: Land Manager

                  Stealth Ventures Ltd.
                  705, 777 - 5 Avenue SW
                  Calgary, AB T2P 3R5
                  Attention: Land Manager

                  Endeavor Energy Corp.
                  1110, 521 - 3 Avenue SW
                  Calgary, AB T2P 3T3
                  Attention: Land Manager

                  Ranchmans Resources Ltd.
                  850, 808 - 4 Avenue SW
                  Calgary, AB T2P 3E8
                  Attention: Land Manager


4.       Article 4.00 (Option Well(s)) will __X__/will not _____ apply.
                                              -
5.       Article 5.00 (Overriding Royalty) will ___X__/will not _____ apply.
                                                   -
6.       Quantification Of Overriding Royalty (Sub clause 5.01A, if applicable)

         (i)  Crude oil (a) -  Alternate - __2__
                            -  If Alternate 1 applies, _____%
                            -  If Alternate 2 applies, __1/23.8365_, min.
                               __5__%, max.__10__%



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         (ii)  Other    (b) -  Alternate - ___1___,
                            -  If Alternate 1 applies, __10__%
                            -  If Alternate 2 applies, ______%, in (i) and
                               _____% in (ii).

7.       Permitted  Deductions (Sub clause 5.04B, if applicable) - Alternate (s)
                          1 only _____,
                          2 only _____,
                          1 and 2 __X__,
                          Neither 1 nor 2 _____.

         If  Alternate  2  applies,  deductions  not   greater  than  ____50___%
         of the Market Price.

8.       Article 6.00 (Conversion Of Overriding  Royalty) - will ______/will not
         __X__ apply.

         If Article 6.00 applies,  conversion  to _____% of Working  Interest in
         Sub clause 6.04A.

9.       Article  8.00 (Area of Mutual  Interest)  - will  _____/will  not __X__
         apply.

10.      Well  Information  To Royalty  Owners (Sub clause 9.03 (b))  amended to
         read as follows:


     "The additional  information described in the well information  requirement
     Schedule and this Article.  However,  if that Royalty Well is being drilled
     to obtain information to evaluate any petroleum and natural gas rights that
     have been  offered  for sale at a Crown land sale  within  three and a half
     (3.5)  kilometers  of the well and the  provisions  of Article 8.00 are not
     then in effect, the obligation to deliver that additional  information will
     be  suspended  until seven (7) days  following  the  applicable  Crown land
     sale."

11.      Reimbursement  Of  Land   Maintenance   Costs  (Clause  11.02)  -  will
         _____/will not __X__apply.

                  If applies, reimbursement of $ ________.







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                                  SCHEDULE "C"
                                  ------------

ATTACHED TO AND FORMING A PART OF A SEISMIC  OPTION  AGREEMENT  DATED  AUGUST 1,
2007 AMONG ENDEAVOR ENERGY CORP.,  RANCHMANS  RESOURCES LTD.,  STEALTH  VENTURES
LTD., AND PANTERRA RESOURCES CORP. -
                               SOUTH SASKATCHEWAN


                          1990 CAPL OPERATING PROCEDURE
                          -----------------------------


     CLAUSES              PAGE                        ELECTIONS
 ---------------------------------------------- --------------------------------
       311                  9                              Insurance
                                                          ___ A xxx B
---------------------------------------------- ---------------------------------
       604                 15                         Marketing Fee xxx A
--------------------------------------------- ----------------------------------
       903                 19                            Casing Point
                                                          xxx A ___ B
---------------------------------------------- ---------------------------------
                                                    Penalty for Independent
                                                          Operations
       1007                23                  (iv)  300% development well
                                                       500% exploratory well
---------------------------------------------- ---------------------------------
       1010                25                        Title Preserving Well
                                                         (iv) 365 days
---------------------------------------------- ---------------------------------
       2401                37                      Disposition of Interests
                                                          xxx A ___ B
---------------------------------------------- ---------------------------------

                                                  Recognition Upon Assignment
       2404                38                      Replaced with 1993 CAPL
                                                   -----------------------
                                                     Assignment Procedure
---------------------------------------------- ---------------------------------




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                           RATES AND ELECTIONS TO THE
                  1996 PETROLEUM ACCOUNTANTS SOCIETY OF CANADA
                           (PASC) ACCOUNTING PROCEDURE


101.     Rates and Elections
         -------------------
         The  following  clauses of the  Accounting  Procedure  are  modified to
         include the indicated election, alternate, option or value:

         105.     Operating Fund:   __10__ %

         110.     Approvals: Clause _____; from __two__ ;  seventy-five  percent
                  (_75_%)

         112.     Expenditure Limitations:

                 (a) excess of  _twenty-five thousand_ dollars ($ 25,000)

                  (c) excess of  _twenty-five thousand_ dollars ($ 25,000)

         202.     Employee Benefits:

                  (b) exceed  twenty-five  percent (_25_%)

         213.     Camp and Housing:

                  (b) shall __x__ / shall not ______

         216.     Warehouse Handling:

                  _2.5_% Warehouse

         221.     Allocation Options:

                  204.       _100% of direct costs_______

                  207 (c).   _100% of direct costs_______

                  212.       _100% of direct costs_______

                  213 (a).  _100% of direct costs_______

                  214.       _100% of direct costs_______

         302.     Overhead Rates:

                  (a) ________ percent (______%)

                                   OR

                      (1) __five___  percent (_5_%); fifty thousand dollars
                         ($50,000.00)

                      (2) __three__  percent  (_3_%); one hundred thousand
                          dollars ($100,000.00)

                      (3) __one___  percent  (_1_%);

                  (b) ________ percent (______%)

                                       OR

                      (1) __three__ percent (_3_%); fifty thousand dollars
                         ($50,000.00)

                      (2) __two __  percent (_2_%); one hundred thousand dollars
                         ($100,000.00)

                      (3) __one___  percent  (_1_%);

                   (c) ________ percent (______%)

                                       OR

                      (1) __five __ percent (_5_%); fifty thousand dollars
                         ($50,000.00)

                      (2) __three_  percent (_3_%); one hundred thousand dollars
                         ($100,000.00)

                     (3) __one__  percent  (_1_%);

                  (d) ________ percent (______%)


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                                       OR

                      (1) __five __ percent (_5_%); fifty thousand dollars
                         ($50,000.00)

                      (2) __three_  percent (_3_%); one hundred thousand dollars
                         ($100,000.00)

                      (3) __one__  percent  (_1_%);

                  (e) ________ percent (______%)

                                       OR

                      (1) __ten __ percent (_10_%); and

                      (2) __two hundred and fifty  dollars ($250.00)

                      (3) ______  percent  (___%);

                       Shall ___x___ / shall not ______

         406.     Dispositions:  fifty thousand  dollars ($50,000.00)

102.     Modifications to the PASC Accounting Procedure

The Accounting Procedure is modified as follows:

        The  clauses  contained  in the  Accounting  Procedure  are  amended as
follows:

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103.     Warranty as to Modifications

Except as otherwise  provided for in Clause 101 and 102 hereof,  the  Accounting
Procedure  published  by the  Petroleum  Accountants  Society  of  Canada,  1996
(copyright)  is hereby  incorporated  in its entirely in the  Agreement  and the
Parties so warrant that said  Accounting  Procedure has been amended only to the
extent set forth herein.











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