**Exhibit
      10.11**





THE
      SECURITIES REPRESENTED BY THIS WARRANT HAVE NOT BEEN REGISTERED UNDER THE
      SECURITIES ACT OF 1933, AS AMENDED, OR APPLICABLE STATE SECURITIES LAWS. THE
      SECURITIES MAY NOT BE OFFERED FOR SALE, SOLD, TRANSFERRED OR ASSIGNED (I) IN
      THE
      ABSENCE OF (A) AN EFFECTIVE REGISTRATION STATEMENT FOR THE SECURITIES UNDER
      THE
      SECURITIES ACT OF 1933, AS AMENDED, OR APPLICABLE STATE SECURITIES LAWS OR
      (B)
      AN OPINION OF COUNSEL, IN A GENERALLY ACCEPTABLE FORM, THAT REGISTRATION IS
      NOT
      REQUIRED UNDER SAID ACT OR APPLICABLE STATE SECURITIES LAWS OR (II) UNLESS
      SOLD
      PURSUANT TO RULE 144 UNDER SAID ACT. NOTWITHSTANDING THE FOREGOING, THE
      SECURITIES MAY BE PLEDGED IN CONNECTION WITH A BONA FIDE MARGIN ACCOUNT OR
      OTHER
      LOAN OR FINANCING ARRANGEMENT SECURED BY THE SECURITIES. ANY TRANSFEREE OF
      THIS
      WARRANT SHOULD CAREFULLY REVIEW THE TERMS OF THIS WARRANT, INCLUDING SECTION
      2(f) HEREOF.
      THE SECURITIES REPRESENTED BY THIS WARRANT MAY BE LESS THAN THE NUMBER SET
      FORTH
      ON THE FACE HEREOF PURSUANT TO SECTION
      2(f) HEREOF.








**SONTERRA
      RESOURCES, INC.**





**Warrant
      To Purchase Common Stock**




Warrant
              No.: CW-001
            Number
                of Shares: 4,958,678Date
              of Issuance: February
              14, 2008




Sonterra
      Resources, Inc. (f/k/a River Capital Group, Inc.), a Delaware corporation (the
      “ **Company** ”),
      hereby certifies that, for Ten United States Dollars ($10.00) and other good
      and
      valuable consideration, the receipt and sufficiency of which are hereby
      acknowledged, The Longview Fund, L.P., a California limited partnership, the
      registered holder hereof or its permitted assigns (the “ **Holder** ”),
      is
      entitled, subject to the terms set forth below, to purchase from the Company,
      at
      any time or times on or after the date hereof, but not after 11:59 P.M. New
      York
      Time on the Expiration Date (as defined herein) Four Million Nine Hundred
      Fifty-Eight Thousand Six Hundred Seventy-Eight (4,958,678) fully paid
      nonassessable shares of Common Stock (as defined in Section
      1(b) )
      of the
      Company (the “ **Warrant
      Shares** ”)
      at the
      Warrant Exercise Price (as defined in Section
      1(b) ) .










Securities
      Exchange Agreement .
      This
      Warrant was issued pursuant to Section
      1 of that
      certain Securities Exchange and Additional Note Purchase Agreement, dated as
      of
      August 3, 2007, between the Company and The Longview Fund, L.P., a California
      limited partnership (as amended by the February 2008 Amendment Agreement, dated
      as of February 14, 2008, and as may be further amended, modified, restated
      or
      supplemented from time to time, the “ **Securities
      Exchange Agreement** ”),
      or
      issued in exchange or substitution therefor or replacement thereof. Each
      capitalized term used, and not otherwise defined, herein shall have the meaning
      ascribed thereto in the Securities Exchange Agreement.




Definitions .
      The
      following words and terms used in this Warrant shall have the following
      meanings:




“ **Approved
      Stock Plan** ”
means
      any employee benefit plan that has been approved by the Board of Directors
      and
      stockholders of the Company after the date of the Securities Exchange Agreement,
      pursuant to which the Company’s securities may be issued to consultants,
      employees, officers and directors for services provided to the
      Company.




“ **Business
      Day** ”
means
      any day other than Saturday, Sunday or other day on which commercial banks
      in
      the City of New York are authorized or required by law to remain
      closed.




“ **Common
      Stock** ”
means
      (A) the Company’s Common Stock, par value $.001 per share, and (B) any
      capital stock into which such Common Stock shall have been changed or any
      capital stock resulting from a reclassification of such Common Stock.




“ **Convertible
      Securities** ”
means
      any stock or securities (other than Options) directly or indirectly convertible
      into or exchangeable or exercisable for Common Stock.




“ **dollar** ”
or
      “ **$** ”
means
      U.S. dollars.




**“Exchange
      Act”** means
      the Securities Exchange Act of 1934, as amended.




“ **Exempted
      Issuances** ”
means
      (I) shares of Common Stock issued or deemed to be issued by the Company pursuant
      to, and in accordance with the terms of, an Approved Stock Plan, provided that
      the Company does not (A) amend any Option to reduce its exercise price, (B)
      cancel any Option and re-grant an Option with a lower exercise price than the
      original exercise price of the cancelled Option, or (C) take any other action
      (whether in the form of an amendment, cancellation or replacement grant) that
      has the effect of repricing an Option, except pursuant to a proportional
      adjustment to the exercise price and number of shares issuable thereunder in
      accordance with such Approved Stock Plan to reflect a stock split dividend
      or
      stock combination with respect to the Common Stock; (II) shares of Common Stock
      issued or deemed to be issued by the Company upon the exercise of any Initial
      Officer Option, provided that the terms of such Initial Officer Option or
      security are not amended or otherwise modified on or after the Exchange Closing
      Date, and provided that the exercise price thereof is not reduced, adjusted
      or
      otherwise modified and the number of shares of Common Stock issuable thereunder
      is not increased (whether by operation of, or in accordance with, the relevant
      governing documents or otherwise) on or after the Exchange Closing Date, except
      pursuant to a proportional adjustment to the exercise price and number of shares
      issuable thereunder in accordance with the 2007 Option Plan to reflect a stock
      split dividend or stock combination with respect to the Common Stock; (III)
      shares of Common Stock issued or deemed to be issued by the Company upon
      exercise of this Warrant or (IV) shares of Common Stock issued to C.K. Cooper
      & Company (“ **CKC** ”)
      as
      compensation for services pursuant to the engagement letter dated July 25,
      2007
      between the Company and CKC.




2




“ **Expiration
      Date** ”
means
      the date that is five (5) years after the Warrant Date (as defined in Section
      12 )
      or, if
      such date does not fall on a Business Day, then the next Business
      Day.




“ **Options** ”
means
      any rights, warrants or options to subscribe for or purchase any Common Stock
      or
      Convertible Securities.




“ **Person** ”
means
      an individual, a limited liability company, a partnership, a joint venture,
      a
      corporation, a trust, an unincorporated organization or a government or any
      department or agency thereof or any other legal entity.




“ **Securities
      Act** ”
means
      the Securities Act of 1933, as amended.




“ **Trading
      Day** ”
means
      any day on which the Common Stock is traded on the Principal Market; provided
      that “Trading Day” shall not include any day on which the Common Stock is
      scheduled to trade, or actually trades, on the Principal Market for less than
      4.5 hours.




“ **Warrant** ”
means
      this Warrant and all warrants issued in exchange, transfer or replacement
      thereof pursuant to the terms of this Warrant.




“ **Warrant
      Exercise Price** ”
shall
      be equal to, with respect to any Warrant Share, $0.30210709, subject to
      adjustment as hereinafter provided.




“ **Weighted
      Average Price** ”
means,
      for any security as of any date, the dollar volume-weighted average price for
      such security on its Principal Market during the period beginning at 9:30 a.m.
      New York City time (or such other time as its Principal Market publicly
      announces is the official open of trading) and ending at 4:00 p.m. New York
      City
      time (or such other time as its Principal Market publicly announces is the
      official close of trading) as reported by Bloomberg Financial Markets (or any
      successor thereto) (“ **Bloomberg** ”)
      through its “Volume at Price” functions, or if the foregoing does not apply, the
      dollar volume-weighted average price of such security in the over-the-counter
      market on the electronic bulletin board for such security during the period
      beginning at 9:30 a.m. New York City time (or such other time as such
      over-the-counter market publicly announces is the official open of trading),
      and
      ending at 4:00 p.m. New York City time (or such other time as such
      over-the-counter market publicly announces is the official close of trading)
      as
      reported by Bloomberg, or, if no dollar volume-weighted average price is
      reported for such security by Bloomberg for such hours, the average of the
      highest closing bid price and the lowest closing ask price of any of the market
      makers for such security as reported in the “pink sheets” by the National
      Quotation Bureau, Inc. If the Weighted Average Price cannot be calculated for
      such security on such date on any of the foregoing bases, the Weighted Average
      Price of such security on such date shall be the fair market value as mutually
      determined by the Company and the Holder. If the Company and the Holder are
      unable to agree upon the fair market value of such security, then such dispute
      shall be resolved pursuant to Section
      2(a) .
      All
      such determinations shall be appropriately adjusted for any stock dividend,
      stock split, stock combination or other similar transaction during any period
      during which the Weighted Average Price is being determined.




3




**Exercise
      of Warrant** **.**




Subject
      to the terms and conditions hereof, this Warrant may be exercised by the Holder
      hereof then registered on the books of the Company, in whole or in part, at
      any
      time on any Business Day on or after the opening of business on the date hereof
      and prior to 11:59 P.M. New York City time on the Expiration Date by (i)
      delivery of a written notice, in the form of the exercise notice attached as Exhibit
      A hereto
      (the “ **Exercise
      Notice** ”),
      of
      the Holder’s election to exercise this Warrant, which notice shall specify the
      number of Warrant Shares to be purchased and, if such exercise is conditioned
      upon consummation of any transaction (“ **Exercise
      Trigger Transaction** ”),
      such
      condition to exercise, (ii) (A) payment to the Company of an amount equal to the
      product of the Warrant Exercise Price multiplied by the number of Warrant Shares
      as to which this Warrant is being exercised (such product, the “ **Aggregate
      Exercise Price** ”)
      by
      wire transfer of immediately available funds (or by check if the Company has
      not
      provided the Holder with wire transfer instructions for such payment), or (B)
      notifying the Company that this Warrant is being exercised pursuant to a
      Cashless Exercise (as defined in Section
      2(e) ),
      and
      (iii) if required by Section
      2(f) unless
      the Holder has previously delivered this Warrant to the Company and it or a
      new
      replacement Warrant has not yet been delivered to the Holder, the surrender
      to a
      common carrier for overnight delivery to the Company as soon as practicable
      following such date, of this Warrant (or an indemnification undertaking, in
      customary form, with respect to this Warrant in the case of its loss, theft
      or
      destruction pursuant to Section
      10 );
      provided, that if such Warrant Shares are to be issued in any name other than
      that of the Holder, such issuance shall be deemed a transfer and the provisions
      of Section
      7 shall be
      applicable. In the event of any exercise of the rights represented by this
      Warrant in compliance with this Section
      2(a) ,
      on the
      second (2 nd )
      Business Day (the “ **Warrant
      Share Delivery Date** ”)
      following the date of its receipt of the Exercise Notice, the Aggregate Exercise
      Price (or notice of Cashless Exercise) and if required by Section
      2(f) (unless
      the Holder has previously delivered this Warrant to the Company and a new or
      replacement Warrant has not yet been delivered to the Holder), this Warrant
      (or
      an indemnification undertaking, in customary form, with respect to this Warrant
      in the case of its loss, theft or destruction pursuant to Section
      10 )
      (the
“ **Exercise
      Delivery Documents** ”)
      (or,
      if the exercise of this Warrant is conditioned upon the consummation of an
      Exercise Trigger Transaction, on the later of such second (2nd) Business Day
      and
      the date of consummation of such Exercise Trigger Transaction), (A) if the
      transfer agent for the Common Stock is participating in The Depository Trust
      Company (“ **DTC** ”)
      Fast
      Automated Securities Transfer Program and the Holder is eligible to receive
      shares through DTC, the Company shall credit such aggregate number of shares
      of
      Common Stock to which the Holder shall be entitled to the Holder’s or its
      designee’s balance account with DTC through its Deposit Withdrawal Agent
      Commission system or (B) if not, the Company shall issue and deliver to the
      address specified in the Exercise Notice, a certificate, registered in the
      name
      of the Holder or its designee, for the number of shares of Common Stock to
      which
      the Holder shall be entitled. Upon the latest of (x) the date of delivery of
      the
      Exercise Notice, (y) the date of delivery of the Aggregate Exercise Price
      referred to in clause (ii)(A) above or notification to the Company of a Cashless
      Exercise referred to in Section
      2(e) ,
      and (z)
      if the exercise of this Warrant is conditioned upon the consummation of an
      Exercise Trigger Transaction, the date of such consummation, the Holder shall
      be
      deemed for all purposes to have become the Holder of record of the Warrant
      Shares with respect to which this Warrant has been exercised (the date thereof
      being referred to as the “ **Deemed
      Issuance Date** ”),
      irrespective of the date of delivery of this Warrant as required by clause
      (iii)
      above or the certificates evidencing such Warrant Shares. In the case of a
      dispute as to the determination of the Warrant Exercise Price, the Weighted
      Average Price of a security or the arithmetic calculation of the number of
      Warrant Shares, the Company shall promptly issue to the Holder the number of
      shares of Common Stock that is not disputed and shall submit the disputed
      determinations or arithmetic calculations to the Holder via facsimile within
      two
      (2) Business Days after receipt of the Holder’s Exercise Notice. If the Holder
      and the Company are unable to agree upon the determination of the Warrant
      Exercise Price, the Weighted Average Price or arithmetic calculation of the
      number of Warrant Shares within one (1) Business Day of such disputed
      determination or arithmetic calculation being submitted to the Holder, then
      the
      Company shall immediately submit via facsimile (i) the disputed determination
      of
      the Warrant Exercise Price or the Weighted Average Price to an independent,
      reputable investment banking firm agreed to by the Company and the Holder or
      (ii) the disputed arithmetic calculation of the number of Warrant Shares to
      an
      independent, reputable certified public accounting firm agreed to by the Company
      and the Holder. The Company shall cause the investment banking firm or the
      accountant, as the case may be, to perform the determinations or calculations
      and notify the Company and the Holder of the results no later than two (2)
      Business Days after the date it receives the disputed determinations or
      calculations. Such investment banking firm’s or accountant’s determination or
      calculation, as the case may be, shall be deemed conclusive absent manifest
      error.




4




If
      this
      Warrant is submitted for exercise, as may be required by Section 2(f) ,
      and
      unless the rights represented by this Warrant shall have expired or shall have
      been fully exercised, the Company shall, as soon as practicable and in no event
      later than three (3) Business Days after receipt of this Warrant (the
“ **Warrant
      Delivery Date** ”)
      and at
      its own expense, issue a new Warrant identical in all respects to this Warrant
      except it shall represent rights to purchase the number of Warrant Shares
      purchasable immediately prior to such exercise under this Warrant, less the
      number of Warrant Shares with respect to which such Warrant is exercised
      (together with, in the case of a Cashless Exercise, the number of Warrant Shares
      surrendered in lieu of payment of the Exercise Price).




No
      fractional shares of Common Stock are to be issued upon the exercise of this
      Warrant, but rather the number of shares of Common Stock issued upon exercise
      of
      this Warrant shall be rounded up or down to the nearest whole number (with
      0.5
      rounded up).




If
      the
      Company shall fail for any reason or for no reason (x) to issue and deliver
      to
      the Holder within two (2) Business Days of receipt of the Exercise Delivery
      Documents a certificate for the number of shares of Common Stock to which the
      Holder is entitled or to credit the Holder’s balance account with DTC for such
      number of shares of Common Stock to which the Holder is entitled upon the
      Holder’s exercise of this Warrant or (y) to issue and deliver to the Holder
      on the Warrant Delivery Date a new Warrant for the number of shares of Common
      Stock to which such holder is entitled pursuant to Section
      2(b) hereof,
      if any, then the Company shall, in addition to any other remedies under this
      Warrant or the Securities Exchange Agreement or otherwise available to such
      holder, including any indemnification under Section
      8 of the
      Securities Exchange Agreement, pay as additional damages in cash to such holder
      on each day after such second (2nd) Business Day that such shares of Common
      Stock are not issued and delivered to the Holder, in the case of clause (x)
      above, or such third (3rd) Business Day that such Warrant is not delivered,
      in
      the case of clause (y) above, an amount equal to the sum of (i) 0.5% of the
      product of (A) the number of shares of Common Stock not issued to the Holder
      on
      or prior to the Warrant Share Delivery Date and (B) the Weighted Average Price
      of the Common Stock on the Warrant Share Delivery Date, in the case of the
      failure to deliver Common Stock, and (ii) if the Company has failed to deliver
      a
      Warrant to the Holder on or prior to the Warrant Delivery Date, 0.5% of the
      product of (x) the number of shares of Common Stock issuable upon exercise
      of
      the Warrant as of the Warrant Delivery Date, and (y) the Weighted Average Price
      of the Common Stock on the Warrant Delivery Date; provided that in no event
      shall cash damages accrue pursuant to this Section
      2(d) during
      the period, if any, in which any Warrant Shares are the subject of a bona fide
      dispute that is subject to and being resolved pursuant to, and in compliance
      with the time periods and other provisions of, the dispute resolution provisions
      of Section
      2(a) .
      Alternatively, at the election of the Holder made in the Holder’s sole
      discretion, the Company shall pay to the Holder, in lieu of the additional
      damages referred to in the preceding sentence (but in addition to all other
      available remedies that the Holder may pursue hereunder and under the Securities
      Exchange Agreement (including indemnification pursuant to Section 8 thereof)),
      110% of the amount that (A) the Holder’s total purchase price (including
      brokerage commissions, if any) for shares of Common Stock purchased to make
      delivery in satisfaction of a sale by such holder of the shares of Common Stock
      to which the Holder is entitled but has not received upon an exercise, exceeds
      (B) the net proceeds received by the Holder from the sale of the shares of
      Common Stock to which the Holder is entitled but has not received upon such
      exercise.




5




Notwithstanding
      anything contained herein to the contrary, at any time after the Warrant Date
      (as defined in Section
      12 )
      that
      all of the Warrant Shares issuable hereunder are not registered and available
      for resale pursuant to an effective registration statement under the Securities
      Act in accordance with the Registration Rights Agreement, for any reason
      whatsoever, including as a result of a Grace Period (as defined in the
      Registration Rights Agreement), or as a result of a limitation on the number
      of
      Warrant Shares that may be registered pursuant to Rule 415 under the Act, the
      Holder may, at its election exercised in its sole discretion, exercise this
      Warrant in whole or in part and, in lieu of making the cash payment otherwise
      contemplated to be made to the Company upon such exercise in payment of the
      Aggregate Exercise Price, elect instead to receive upon such exercise the “Net
      Number” of shares of Common Stock determined according to the following formula
      (a “ **Cashless
      Exercise** ”):




Net
      Number = (A
      x
      B) - (A x C)


B


For
      purposes of the foregoing formula:





A=
      the
      total number of shares with respect to which this Warrant is then being
      exercised;





B=
      the
      Weighted Average Price per share of Common Stock on the Trading Day immediately
      preceding the date of the delivery of the Exercise Notice; and





C=
      the
      Warrant Exercise Price then in effect for the applicable Warrant Shares at
      the
      time of such exercise.





Book-Entry .
      Notwithstanding anything to the contrary set forth herein, upon exercise of
      this
      Warrant in accordance with the terms hereof, the Holder shall not be required
      to
      physically surrender this Warrant to the Company unless it is being exercised
      for all of the Warrant Shares represented by the Warrant. The Holder and the
      Company shall maintain records showing the number of Warrant Shares exercised
      and issued and the dates of such exercises or shall use such other method,
      reasonably satisfactory to the Holder and the Company, so as not to require
      physical surrender of this Warrant upon each such exercise. In the event of
      any
      dispute or discrepancy, such records of the Company establishing the number
      of
      Warrant Shares to which the Holder is entitled shall be controlling and
      determinative in the absence of error. Notwithstanding the foregoing, if this
      Warrant is exercised as aforesaid, the Holder may not transfer this Warrant
      unless the Holder first physically surrenders this Warrant to the Company,
      whereupon the Company will forthwith issue and deliver upon the order of the
      Holder a new Warrant of like tenor, registered as the Holder may request,
      representing in the aggregate the remaining number of Warrant Shares represented
      by this Warrant. The Holder and any assignee, by acceptance of this Warrant,
      acknowledge and agree that, by reason of the provisions of this paragraph,
      following exercise of any portion of this Warrant, the number of Warrant Shares
      represented by this Warrant may be less than the number stated on the face
      hereof.




**Covenants
      as to Common Stock** **.
      The Company hereby covenants and agrees as follows:**




This
      Warrant is, and any Warrants issued in substitution for or replacement of this
      Warrant will upon issuance be, duly authorized and validly issued.




All
      Warrant Shares that may be issued upon the exercise of the rights represented
      by
      this Warrant will, upon issuance and receipt of payment therefor from the Holder
      (including pursuant to a Cashless Exercise, as applicable), be validly issued,
      fully paid and nonassessable and free from all taxes, liens and charges with
      respect to the issue thereof.




During
      the period within which the rights represented by this Warrant may be exercised,
      the Company will at all times have authorized and reserved at least 100% of
      the
      number of shares of Common Stock needed to provide for the exercise of the
      rights then represented by this Warrant.




The
      Company shall promptly secure the quotation or listing of the Warrant Shares
      on
      the Principal Market (subject to official notice of issuance upon exercise
      of
      this Warrant) and each other market or exchange on which the Common Stock is
      traded or listed and shall maintain, so long as any other shares of Common
      Stock
      shall be so traded or listed, such listing of all Warrant Shares from time
      to
      time issuable upon the exercise of this Warrant; and the Company shall so list
      on the Principal Market and each other market or exchange on which the Common
      Stock is traded or listed and shall maintain such listing of, any other shares
      of capital stock of the Company issuable upon the exercise of this Warrant
      if
      and so long as any shares of the same class shall be listed on the Principal
      Market and each other market or exchange on which such shares are traded or
      listed.




6




The
      Company will not, by amendment of its Certificate of Incorporation or through
      any reorganization, transfer of assets, consolidation, merger, dissolution,
      issue or sale of securities, or any other voluntary action, avoid or seek to
      avoid the observance or performance of any of the terms to be observed or
      performed by it hereunder, but will at all times in good faith assist in the
      carrying out of all the provisions of this Warrant and in the taking of all
      such
      action as may reasonably be requested by the Holder in order to protect the
      exercise privilege of the Holder against impairment, consistent with the tenor
      and purpose of this Warrant. Without limiting the generality of the foregoing,
      the Company (i) will not increase the par value of any shares of Common
      Stock receivable upon the exercise of this Warrant, and (ii) will take all
      such actions as may be necessary or appropriate in order that the Company may
      validly and legally issue fully paid and nonassessable shares of Common Stock
      upon the exercise of this Warrant.




This
      Warrant will be binding upon any entity succeeding to the Company by merger,
      consolidation or acquisition of all or substantially all of the Company’s
      assets.




**Taxes** **.
      The Company shall pay any and all taxes that may be payable with respect to
      the
      issuance and delivery of Warrant Shares upon exercise of this
      Warrant.**




**Warrant
      Holder Not Deemed a Stockholder** **.
      Except as expressly provided herein, the Holder, as holder of this Warrant
      shall
      not be entitled to vote or be deemed the holder of stock of the Company for
      any
      purpose (other than to the extent that the Holder is deemed to be a beneficial
      holder of Warrant Shares under applicable securities laws), or otherwise have
      any of the rights of a stockholder of the Company or any right to vote, give
      or
      withhold consent to any corporate action (whether any reorganization, issue
      of
      stock, reclassification of stock, consolidation, merger, conveyance or
      otherwise), receive notice of meetings, or receive dividends or subscription
      rights, prior to the Deemed Issuance Date of the Warrant Shares that such holder
      is then entitled to receive upon the due exercise of this Warrant. In addition,
      nothing contained in this Warrant shall be construed as imposing any liabilities
      on such holder to purchase any securities (except to the extent set forth in
      an
      Exercise Notice that has been delivered by the Holder to the Company) or as
      a
      stockholder of the Company, whether such liabilities are asserted by the Company
      or by creditors of the Company. Notwithstanding the foregoing, the Company
      will
      provide the Holder with copies of the same notices (without duplication if
      the
      Holder is also a stockholder of the Company) and other information given to
      the
      stockholders of the Company generally, contemporaneously with the giving thereof
      to the stockholders.**




7




**Representations
      of Holder** **.
      The holder of this Warrant, by the acceptance hereof, represents that it is
      acquiring this Warrant, and upon exercise hereof (other than pursuant to a
      Cashless Exercise) will acquire the Warrant Shares, for its own account and
      not
      with a view towards, or for resale in connection with, the public sale or
      distribution of this Warrant or the Warrant Shares, except pursuant to sales
      registered, or exempted from registration, under the Securities Act; provided,
      however, that by making the representations herein, the Holder does not agree
      to
      hold this Warrant or any of the Warrant Shares for any minimum or other specific
      term and reserves the right to dispose of this Warrant and the Warrant Shares
      at
      any time in accordance with or pursuant to a registration statement or an
      exemption under the Securities Act. The holder of this Warrant further
      represents, by acceptance hereof, that, as of this date, such holder is an
      “accredited investor” as such term is defined in Rule 501(a)(3) of Regulation D
      promulgated by the Securities and Exchange Commission under the Securities
      Act.
      Each delivery of an Exercise Notice, other than in connection with a Cashless
      Exercise, shall constitute confirmation at such time by the Holder of the
      representations concerning the Warrant Shares set forth in the first two
      sentences of this** **Section
      6** **,
      unless contemporaneously with the delivery of such Exercise Notice, the Holder
      notifies the Company in writing that it is not making such representations
      (a
“** Representation
      Notice **”).
      If the Holder delivers a Representation Notice in connection with an exercise,
      it shall be a condition to such Holder’s exercise of this Warrant and the
      Company’s obligations set forth in** **Section
      2** **in connection with such exercise, that the Company receive such other
      representations as the Company considers reasonably necessary to assure the
      Company that the issuance of its securities upon exercise of this Warrant shall
      not violate any United States or state securities laws.**




**Ownership
      and Transfer** **.**




The
      Company shall maintain at its principal executive offices (or such other office
      or agency of the Company as it may designate by notice to the Holder), a
      register for this Warrant, in which the Company shall record the name and
      address of the person in whose name this Warrant has been issued, as well as
      the
      name and address of each transferee. The Company may treat the person in whose
      name any Warrant is registered on the register as the owner and holder thereof
      for all purposes, notwithstanding any notice to the contrary, but in all events
      recognizing any transfers made in accordance with the terms of this
      Warrant.




This
      Warrant and the rights granted hereunder shall be assignable by the Holder
      hereof in accordance with the Securities Exchange Agreement.




The
      Company is obligated to register the Warrant Shares for resale under the
      Securities Act pursuant to the Registration Rights Agreement and the initial
      holder of this Warrant (and certain assignees thereof) is entitled to the
      registration rights in respect of the Warrant Shares as set forth in the
      Registration Rights Agreement.




8




**Adjustment
      of Warrant Exercise Price and Number of Warrant Shares** **.
      The Warrant Exercise Price and the number of shares of Common Stock issuable
      upon exercise of this Warrant shall be adjusted from time to time as follows:**




Adjustment
      of Warrant Exercise Price and Number of Shares upon Issuance of Common
      Stock .
      If and
      whenever on or after the Warrant Date (as defined in Section
      12 ),
      the
      Company issues or sells, or is deemed to have issued or sold, any shares of
      Common Stock (including the issuance or sale of shares of Common Stock owned
      or
      held by or for the account of the Company, but excluding Exempted Issuances),
      for a consideration per share less than a price (the “ **Applicable
      Price** ”)
      equal
      to the Warrant Exercise Price in effect immediately prior to such issuance
      or
      sale, then immediately after such issue or sale the Warrant Exercise Price
      then
      in effect shall be reduced to an amount equal to such consideration per share.
      Upon each such adjustment of the Warrant Exercise Price pursuant to the
      immediately preceding sentence, the number of shares of Common Stock acquirable
      upon exercise of this Warrant shall be adjusted to the number of shares
      determined by multiplying the Warrant Exercise Price in effect immediately
      prior
      to such adjustment by the number of shares of Common Stock acquirable upon
      exercise of this Warrant immediately prior to such adjustment and dividing
      the
      product thereof by the Warrant Exercise Price resulting from such adjustment.




Effect
      on Warrant Exercise Price of Certain Events .
      For all
      purposes of this Section
      8 ,
      including for purposes of determining the adjusted Warrant Exercise Price under Section
      8(a) above
      and for purposes of determining whether the Company has issued or sold, or
      shall
      be deemed to have issued or sold, any shares of Common Stock for a consideration
      per share less than a price equal to the Applicable Price), the following shall
      be applicable:




Issuance
      of Options .
      If the
      Company in any manner grants or sells any Options (other than pursuant to an
      Approved Stock Plan) and the lowest price per share for which one share of
      Common Stock is issuable upon the exercise of any such Option or upon
      conversion, exchange or exercise of any Convertible Securities issuable upon
      exercise of any such Option is less than the Applicable Price, then such share
      of Common Stock shall be deemed to be outstanding and to have been issued and
      sold by the Company at the time of the granting or sale of such Option for
      such
      price per share. For purposes of this Section
      8(b)(i) ,
      the
“lowest price per share for which one share of Common Stock is issuable upon
      exercise of any such Option or upon conversion, exchange or exercise of any
      Convertible Security issuable upon exercise of any such Option” shall be equal
      to the sum of the lowest amounts of consideration (if any) received or
      receivable by the Company with respect to any one share of Common Stock upon
      the
      granting or sale of the Option, upon exercise of the Option and upon conversion,
      exchange or exercise of any Convertible Security issuable upon exercise of
      such
      Option. No further adjustment of the Warrant Exercise Price shall be made upon
      the actual issuance of such Common Stock or of such Convertible Securities
      upon
      the exercise of such Options or upon the actual issuance of such Common Stock
      upon conversion, exchange or exercise of such Convertible
      Securities.





9




Issuance
      of Convertible Securities .
      If the
      Company in any manner issues or sells any Convertible Securities and the lowest
      price per share for which one share of Common Stock is issuable upon the
      conversion, exchange or exercise thereof is less than the Applicable Price,
      then
      such share of Common Stock shall be deemed to be outstanding and to have been
      issued and sold by the Company at the time of the issuance or sale of such
      Convertible Securities for such price per share. For the purposes of this Section
      8(b)(ii) ,
      the
“lowest price per share for which one share of Common Stock is issuable upon
      such conversion, exchange or exercise” shall be equal to the sum of the lowest
      amounts of consideration (if any) received or receivable by the Company with
      respect to one share of Common Stock upon the issuance or sale of the
      Convertible Security and upon conversion, exchange or exercise of such
      Convertible Security. No further adjustment of the Warrant Exercise Price shall
      be made upon the actual issuance of such Common Stock upon conversion, exchange
      or exercise of such Convertible Securities, and if any such issue or sale of
      such Convertible Securities is made upon exercise of any Options for which
      adjustment of the Warrant Exercise Price had been or are to be made pursuant
      to
      other provisions of this Section
      8(b) ,
      no
      further adjustment of the Warrant Exercise Price shall be made by reason of
      such
      issue or sale.




Change
      in Option Price or Rate of Conversion. If the
      purchase, exchange or exercise price provided for in any Options, the additional
      consideration, if any, payable upon the issue, conversion, exchange or exercise
      of any Convertible Securities, or the rate at which any Options or Convertible
      Securities are convertible into or exchangeable or exercisable for Common Stock
      changes at any time, the Warrant Exercise Price in effect at the time of such
      change shall be adjusted to the Warrant Exercise Price that would have been
      in
      effect at such time had such Options or Convertible Securities provided for
      such
      changed purchase, exchange or exercise price, additional consideration or
      changed conversion rate, as the case may be, at the time initially granted,
      issued or sold, and the number of shares of Common Stock acquirable hereunder
      shall be correspondingly readjusted. For purposes of this Section
      8(b)(iii) ,
      if the
      terms of any Option or Convertible Security that was outstanding as of the
      date
      of issuance of this Warrant are changed in the manner described in the
      immediately preceding sentence, then such Option or Convertible Security and
      the
      Common Stock deemed issuable upon exercise, conversion or exchange thereof
      shall
      be deemed to have been issued as of the date of such change. No adjustment
      shall
      be made if such adjustment would result in an increase of the Warrant Exercise
      Price then in effect.




Calculation
      of Consideration Received .
      In case
      any Options are issued in connection with the issue or sale of other securities
      of the Company, together comprising one integrated transaction or series of
      related transactions, (A) the Options will be deemed to have been issued for
      a
      consideration equal to the greatest of (I) $0.01, (II) the specific aggregate
      consideration, if any, allocated to such Options, and (III) the Black-Scholes
      Value (as defined below) of such Options (the greatest of (I), (II) and (III),
      the “ **Option
      Consideration** ”)
      and,
      for purposes of applying the provisions of this Section
      8 ,
      the
      Option Consideration shall be allocated pro rata among all the shares of Common
      Stock issuable upon exercise of such Options to determine the consideration
      per
      each such share of Common Stock and (B) the other securities will be deemed
      to
      have been issued for an aggregate consideration equal to the aggregate
      consideration received by the Company for the Options and other securities
      (determined as provided below with respect to each share of Common Stock
      represented thereby), less the Option Consideration. If any Common Stock,
      Options or Convertible Securities are issued or sold or deemed to have been
      issued or sold for cash, the consideration received therefor will be deemed
      to
      be the net amount received by the Company therefor. If any Common Stock, Options
      or Convertible Securities are issued or sold for a consideration other than
      cash, the amount of such consideration received by the Company will be the
      fair
      value of such consideration, except where such consideration consists of
      marketable securities, in which case the amount of consideration received by
      the
      Company will be the Weighted Average Price of such securities on the date of
      receipt of such securities. If any Common Stock, Options or Convertible
      Securities are issued to the owners of the non-surviving entity in connection
      with any merger in which the Company is the surviving entity, the amount of
      consideration therefor will be deemed to be the fair value of such portion
      of
      the net assets and business of the non-surviving entity as is attributable
      to
      such Common Stock, Options or Convertible Securities, as the case may be. The
      fair value of any consideration other than cash or securities will be determined
      jointly by the Company and the Holder. If such parties are unable to reach
      agreement within ten (10) days after the occurrence of an event requiring
      valuation (the “ **Valuation
      Event** ”),
      the
      fair value of such consideration will be determined within five (5) Business
      Days after the tenth (10th) day following the Valuation Event by an independent,
      reputable appraiser jointly selected by the Company and the Holder. The
      determination of such appraiser shall be final and binding upon all parties
      absent manifest error, and the fees and expenses of such appraiser shall be
      borne by the Company.




10




Record
      Date .
      If the
      Company takes a record of the Holders of Common Stock for the purpose of
      entitling them (1) to receive a dividend or other distribution payable in Common
      Stock, Options or in Convertible Securities or (2) to subscribe for or purchase
      Common Stock, Options or Convertible Securities, then such record date will
      be
      deemed to be the date of the issue or sale of the shares of Common Stock deemed
      to have been issued or sold upon the declaration of such dividend or the making
      of such other distribution or the date of the granting of such right of
      subscription or purchase, as the case may be.




Black-Scholes
      Value .
      The
“ **Black-Scholes
      Value** ”
of
      any
      Options shall mean the sum of the amounts resulting from applying the *Black-Scholes* pricing
      model to each such Option, which calculation is made with the following inputs:
      (i) the “option striking price” being equal to the lowest exercise price
      possible under the terms of such Option on the date of the issuance of such
      Option (the “ **Valuation
      Date** ”),
      (ii)
      the “interest rate” being equal to the Federal Reserve US H.15 T Note Treasury
      Constant Maturity 1 Year rate on the Valuation Date (as reported by Bloomberg
      through its "ALLX H15T" function (accessed by typing "ALLX H15T" [GO] on a
      Bloomberg terminal, and inserting the date of the Valuation Date and then
      looking at the row entitled "Treas Const Mat 1 Year" under the column entitled
      “Previous Value”)), or if such rate is not available then such other similar
      rate mutually agreed to by the Company and the Holder, (iii) the “time until
      option expiration” being the time from the Valuation Date until the expiration
      date of such Option, (iv) the “current stock price” being equal to the Weighted
      Average Price of the Common Stock on the Valuation Date, (v) the “volatility”
being the 100-day historical volatility of the Common Stock as of the Valuation
      Date (as reported by the Bloomberg “HVT” screen), and (vi) the “dividend rate”
being equal to zero. Within three (3) Business Days after the Valuation Date,
      each of the Company and the Holder shall deliver to the other a written
      calculation of its determination of the Black-Scholes Value of the Options.
      If
      the Holder and the Company are unable to agree upon the calculation of the
      Black-Scholes Value of the Options within five (5) Business Days of the
      Valuation Date, then the Company shall submit via facsimile the disputed
      calculation to an independent, reputable investment banking firm (jointly
      selected by the Company and the Holder) within seven (7) Business Days of the
      Valuation Date. The Company shall cause such investment banking firm to perform
      the calculations and notify the Company and the Holder of the results no later
      than ten (10) Business Days after the Valuation Date. Such investment banking
      firm’s calculation of the Black-Scholes Value of the Options shall be deemed
      conclusive absent manifest error. The Company shall bear the fees and expenses
      of such investment banking firm for providing such calculation.




11




Adjustment
      of Warrant Exercise Price upon Subdivision or Combination of Common
      Stock .
      If the
      Company at any time after the date of issuance of this Warrant subdivides (by
      any stock split, stock dividend, recapitalization or otherwise) its outstanding
      shares of Common Stock into a greater number of shares, the Warrant Exercise
      Price in effect immediately prior to such subdivision will be proportionately
      reduced and the number of shares of Common Stock obtainable upon exercise of
      this Warrant will be proportionately increased. If the Company at any time
      after
      the date of issuance of this Warrant combines (by combination, reverse stock
      split or otherwise) its outstanding shares of Common Stock into a smaller number
      of shares, the Warrant Exercise Price in effect immediately prior to such
      combination will be proportionately increased and the number of shares of Common
      Stock obtainable upon exercise of this Warrant will be proportionately
      decreased. Any adjustment under this Section
      8(d) shall
      become effective at the close of business on the date the subdivision or
      combination becomes effective or, if earlier, the record date with respect
      to
      the subdivision or combination.




Dividends;
      Distributions of Assets .
      If the
      Company shall declare or make any dividend or other distribution of its assets
      (or rights to acquire its assets) to holders of Common Stock, by way of return
      of capital or otherwise (including any dividend or other distribution of cash,
      stock or other securities, property or options by way of a dividend, spin off,
      reclassification, corporate rearrangement or other similar transaction) (a
      “ **Distribution** ”),
      at
      any time after the issuance of this Warrant, then, in each such case, the Holder
      shall be entitled to receive such Distribution, and the Company shall make
      such
      Distribution to the Holder, exactly as if the Holder had exercised this Warrant
      in full (and, as a result, had held all of the shares of Common Stock that
      the
      Holder would have received upon such exercise) immediately prior to the record
      date for such Distribution, or if there is no record therefor, immediately
      prior
      to the effective date of such Distribution (but without the Holder’s actually
      having to so exercise this Warrant).




Certain
      Events .
      If any
      event occurs of the type contemplated by the provisions of this Section
      8 but not
      expressly provided for by such provisions (including the granting of stock
      appreciation rights, phantom stock rights or other rights with equity features),
      then the Company’s Board of Directors will make an appropriate adjustment in the
      Warrant Exercise Price and the number of shares of Common Stock obtainable
      upon
      exercise of this Warrant so as to protect the rights of the Holder; provided
      that no such adjustment will increase the Warrant Exercise Price or decrease
      the
      number of shares of Common Stock obtainable as otherwise determined pursuant
      to
      this Section
      8 .




12




Notices .




As
      soon
      as reasonably practicable, but in no event later than two (2) Business Days,
      upon any adjustment of the Warrant Exercise Price, the Company will give written
      notice thereof to the Holder, setting forth in reasonable detail, and
      certifying, the calculation of such adjustment; provided, however, that neither
      the timing of giving any such notice nor any failure by the Company to give
      such
      a notice shall effect any such adjustment or the effective date
      thereof.




The
      Company will give written notice to the Holder at least ten (10) days prior
      to
      the date on which the Company closes its books or takes a record (A) with
      respect to any dividend or distribution upon the Common Stock, (B) with respect
      to any pro rata subscription offer to holders of Common Stock or (C) for
      determining rights to vote with respect to any Organic Change (as defined
      below), dissolution or liquidation.




The
      Company will also give written notice to the Holder at least ten (10) days
      prior
      to the date on which any Organic Change, dissolution or liquidation will take
      place.




**Purchase
      Rights; Reorganization, Reclassification, Consolidation, Merger or
      Sale** **.**




In
      addition to any adjustments pursuant to Section
      8 above,
      if at any time the Company grants, issues or sells any Options, Convertible
      Securities or rights to purchase stock, warrants, securities or other property
      pro rata to the record holders of any class of its capital stock (the
“ **Purchase
      Rights** ”),
      then
      the Holder will be entitled to acquire, upon the terms applicable to such
      Purchase Rights, the aggregate Purchase Rights that such holder could have
      acquired if such holder had held the number of shares of Common Stock acquirable
      upon complete exercise of this Warrant immediately before the date on which
      a
      record is taken for the grant, issuance or sale of such Purchase Rights, or,
      if
      no such record is taken, the date as of which the record holders of Common
      Stock
      are to be determined for the grant, issue or sale of such Purchase
      Rights.




Any
      recapitalization, reorganization, reclassification, consolidation, merger,
      sale
      of all or substantially all of the Company’s assets to another Person or other
      transaction that is effected in such a way that holders of Common Stock are
      entitled to receive (either directly or upon subsequent liquidation) stock,
      securities or assets with respect to or in exchange for Common Stock is referred
      to herein as “ **Organic
      Change** .”
Prior
      to the consummation of any (i) sale of all or substantially all of the Company’s
      assets to an acquiring Person or (ii) other Organic Change following which
      the
      Company is not a surviving entity, the Company will secure from the Person
      purchasing such assets or the successor resulting from such Organic Change
      (in
      each case, the “ **Acquiring
      Entity** ”)
      a
      written agreement (in form and substance satisfactory to the Holder) to deliver
      to the Holder, in exchange for this Warrant, a security of the Acquiring Entity
      evidenced by a written instrument substantially similar in form and substance
      to
      this Warrant and satisfactory to the Holder (including, an adjusted Warrant
      Exercise Price equal to the value for the Common Stock reflected by the terms
      of
      such consolidation, merger or sale, and exercisable for a corresponding number
      of shares of Common Stock acquirable and receivable upon exercise of this
      Warrant, if the value so reflected is less than the Warrant Exercise Price
      in
      effect immediately prior to such consolidation, merger or sale). Prior to the
      consummation of any other Organic Change, the Company shall make appropriate
      provision (in form and substance satisfactory to the Holder) to ensure that
      the
      Holder will thereafter have the right to acquire and receive in lieu of or
      in
      addition to (as the case may be) the shares of Common Stock immediately
      theretofore acquirable and receivable upon the exercise of such this Warrant,
      such shares of stock, securities or assets that would have been issued or
      payable in such Organic Change with respect to or in exchange for the number
      of
      shares of Common Stock that would have been acquirable and receivable upon
      the
      exercise of this Warrant as of the date of such Organic Change.




13




**Lost,
      Stolen, Mutilated or Destroyed Warrant** **.
      If this Warrant is lost, stolen, mutilated or destroyed, the Company shall
      promptly, on receipt of an indemnification undertaking in customary form (or
      in
      the case of a mutilated Warrant, the Warrant), issue a new Warrant of like
      denomination and tenor as this Warrant so lost, stolen, mutilated or
      destroyed.**




**Notice** **.
      Any notices, consents, waivers or other communications required or permitted
      to
      be given under the terms of this Warrant must be in writing and will be deemed
      to have been delivered: (i) upon receipt, when delivered personally; (ii) upon
      receipt, when sent by facsimile (provided confirmation of transmission is
      mechanically or electronically generated and kept on file by the sending party);
      or (iii) one (1) Business Day after deposit with a nationally recognized
      overnight delivery service, in each case properly addressed to the party to
      receive the same. The addresses and facsimile numbers for such communications
      shall be:**




If
      to the
      Company:





Sonterra
      Resources, Inc.


300
      East
      Sonterra Boulevard, Suite 1220


San
      Antonio, Texas


Facsimile:
      210-545-3317


Attention:
      Michael J. Pawelek





With
      a
      copy to:





Thompson
      & Knight


333
      Clay
      Street, Suite 3300


Houston,
      Texas 77002


Facsimile:
      832-397-8110


Attention:
      Dallas Parker, Esq.





If
      to the
      initial Holder, to it at the address and facsimile number set forth in the
      Securities Exchange Agreement, with copies to the Holder’s representatives as
      set forth in the Securities Exchange Agreement or, in the case of any other
      Holder or any other Person named above, at such other address and/or facsimile
      number and/or to the attention of such other person as the recipient party
      has
      specified by written notice to the other party at least five (5) Business Days
      prior to the effectiveness of such change. Written confirmation of receipt
      (A)
      given by the recipient of such notice, consent, waiver or other communication,
      (B) mechanically or electronically generated by the sender’s facsimile machine
      containing the time, date, recipient facsimile number and an image of the first
      page of such transmission or (C) provided by a nationally recognized overnight
      delivery service shall be rebuttable evidence of personal service, receipt
      by
      facsimile or deposit with a nationally recognized overnight delivery service
      in
      accordance with clause (i), (ii) or (iii) above, respectively.




14





**Date** **.
      The date of this Warrant is February 14, 2008 (the “** Warrant
      Date **”).
      This Warrant, in all events, shall be wholly void and of no effect after
      11:59 P.M., New York City time, on the Expiration Date, except that
      notwithstanding any other provisions hereof, the provisions of** **Section
      7** **shall continue in full force and effect after such date as to any Warrant Shares
      or other securities issued upon the exercise of this
      Warrant.**




**Amendment
      and Waiver** **.
      Except as otherwise provided herein, the provisions of this Warrant may be
      amended and the Company may take any action herein prohibited, or omit to
      perform any act herein required to be performed by it, only if the Company
      has
      obtained the written consent of the Holder.**




**Descriptive
      Headings; Governing Law** **.
      The descriptive headings of the several sections and paragraphs of this Warrant
      are inserted for convenience only and do not constitute a part of this Warrant.
      All questions concerning the construction, validity, enforcement and
      interpretation of this Warrant shall be governed by the internal laws of the
      State of New York, without giving effect to any choice of law or conflict of
      law
      provision or rule (whether of the State of New York or any other jurisdiction)
      that would cause the application of the laws of any jurisdiction other than
      the
      State of New York.**




**Rules
      of Construction** **.
      Unless the context otherwise requires, (a) all references to Articles, Sections,
      Schedules or Exhibits are to Articles, Sections, Schedules or Exhibits contained
      in or attached to this Warrant, (b) each accounting term not otherwise defined
      in this Warrant or the Securities Exchange Agreement has the meaning assigned
      to
      it in accordance with GAAP, (c) words in the singular or plural include the
      singular and plural and pronouns stated in either the masculine, the feminine
      or
      neuter gender shall include the masculine, feminine and neuter and (d) the
      use
      of the word “including” in this Warrant shall be by way of example rather than
      limitation.**




**Signatures** **.**  **In
      the event that any signature to this Warrant or any amendment hereto is
      delivered by facsimile transmission or by e-mail delivery of a “.pdf” format
      data file, such signature shall create a valid and binding obligation of the
      party executing (or on whose behalf such signature is executed) with the same
      force and effect as if such facsimile or “.pdf” signature page were an original
      thereof. Notwithstanding the foregoing, the Company shall be obligated to
      deliver to the Holder an originally executed Warrant. At the request of any
      party, each other party shall promptly re-execute an original form of this
      Warrant or any amendment hereto and deliver the same to the other party. No
      party hereto shall raise the use of a facsimile machine or e-mail delivery
      of a
“.pdf” format data file to deliver a signature to this Warrant or any amendment
      hereto or the fact that such signature was transmitted or communicated through
      the use of a facsimile machine or e-mail delivery of a “.pdf” format data file
      as a defense to the formation or enforceability of a contract, and each party
      hereto forever waives any such defense.**




***
      * * * * ***




15


**IN
      WITNESS WHEREOF** ,
      the
      Company has caused this Warrant to be executed as of February 14,
      2008.





**SONTERRA
              RESOURCES, INC. (f/k/a River Capital Group, Inc.)**By: /s/ Howard
              TaylorName:Howard
              TaylorTitle:   
              Chief
              Executive Officer




16


**EXHIBIT
      A TO WARRANT**




**EXERCISE
      NOTICE**




TO
      BE
      EXECUTED BY THE REGISTERED HOLDER TO EXERCISE THIS WARRANT




**SONTERRA
      RESOURCES, INC.**




The
      undersigned holder hereby exercises the right to purchase _________________
      of
      the shares of Common Stock (“ **Warrant
      Shares** ”)
      of
      SONTERRA RESOURCES, INC. (f/k/a River Capital Group, Inc.), a Delaware
      corporation (the “ **Company** ”),
      evidenced by the attached Warrant (the “ **Warrant** ”).
      Capitalized terms used herein and not otherwise defined shall have the
      respective meanings set forth in the Warrant.




1.
      Form
      of Warrant Exercise Price. The holder intends that payment of the Warrant
      Exercise Price shall be made as:




____________ a
      “ **Cash
      Exercise** ” with
      respect to ___________________ Warrant Shares; and/or




____________ a
      “ **Cashless
      Exercise** ”
with
      respect to ______________ Warrant Shares.




2.
      Payment of Warrant Exercise Price. In the event that the Holder has elected
      a
      Cash Exercise with respect to some or all of the Warrant Shares to be issued
      pursuant hereto, the Holder shall pay the Aggregate Exercise Price in the sum
      of
      $___________________ to the Company in accordance with the terms of the
      Warrant.




3.
      Exercise Trigger Transaction. This exercise of the Warrant is conditioned upon
      the consummation of the following Exercise Trigger Transaction:
      __________________________ 1   No
      such condition applies if left blank




4.
      Delivery of Warrant Shares. The Company shall deliver __________ Warrant Shares
      in accordance with the terms of the Warrant in the following name and to the
      following address:




Issue
      to:




Facsimile
      Number:
      _______________________________________________________________




DTC
      Participant Number and Name (if electronic book entry transfer):
      ________________________




Account
      Number (if electronic book entry transfer):
      _____________________________________




Date:
      _______________ __, ______




Name
      of
      Registered Holder of this Warrant


____________________________




________ 1 No such
        condition applies if left blank




17




By:
      __________________________


Name:


Title:


**ACKNOWLEDGMENT**




The
      Company hereby acknowledges this Exercise Notice and hereby directs [TRANSFER
      AGENT] to issue the above indicated number of shares of Common Stock in
      accordance with the Transfer Agent Instructions dated ________________, 200_
      from the Company and acknowledged and agreed to by [TRANSFER
      AGENT].




**SONTERRA
              RESOURCES, INC.**By:
              ________________________Name:
              ______________________Title:
              _______________________


18


**EXHIBIT
      B TO WARRANT**





FORM
      OF
      WARRANT POWER








FOR
      VALUE
      RECEIVED, the undersigned does hereby assign and transfer to ________________,
      Federal Identification No. __________, a warrant to purchase ____________ shares
      of the capital stock of Sonterra Resources, Inc. (f/k/a River Capital Group,
      Inc.), a Delaware corporation, represented by warrant certificate no. _____,
      standing in the name of the undersigned on the books of said corporation. The
      undersigned does hereby irrevocably constitute and appoint ______________,
      attorney to transfer the warrants of said corporation, with full power of
      substitution in the premises.








Dated:
      _________, 200_








_________________________________
              
              Name:____________________________
              Title:_____________________________





19