EXHIBIT
99.1
 
 
 February
17, 2010
 
 XTO
Energy Inc.
 810
Houston Street, Suite 2000
 Fort
Worth, TX  76102
 Re:          Underlying
Properties (100%)
 Relating
to the Hugoton Royalty Trust
 As of
December 31, 2009 - SEC Pricing Case
 Gentlemen:
 
 At your
request, Miller and Lents, Ltd. (MLL) estimated the proved reserves and future
net revenues as of December 31, 2009, attributable to the XTO Energy Inc. (XTO)
interest in certain oil and gas properties prior to inclusion in the Hugoton
Royalty Trust, i.e., Underlying Properties (100%).  The properties
consist of approximately 1,672 leases and 1,821 wells located in Kansas,
Oklahoma, and Wyoming.  The aggregate results of MLL’s evaluations are
as follows:
 
 Net
      Reserves
              Future
      Net RevenuesReserves
      Category
              Oil
      and
                Condensate,
                MBbls.
              Gas,
                MMcf
              Undiscounted,
                M$
              Discounted
      at
                10%
      Per Year,
                M$KansasProved
      Developed Producing
              293.4
              22,096.3
              54,410.3
              32,037.9Proved
      Nonproducing
              0.0
              417.5
              982.8
              454.8Proved
      Undeveloped
              99.2
              2,068.8
              6,086.2
              3,019.1Subtotal
              392.6
              24,582.6
              61,479.3
              35,511.8OklahomaProved
      Developed Producing
              2,145.1
              184,934.7
              453,579.6
              250,968.7Proved
      Nonproducing
              31.8
              2,434.7
              6,324.8
              2,644.6Proved
      Undeveloped
              333.9
              25,629.7
              30,951.7
              -1,405.3Subtotal
              2,510.8
              212,999.1
              490,856.1
              252,208.0WyomingProved
      Developed Producing
              90.0
              73,981.0
              94,697.9
              57,584.9Proved
      Undeveloped
              11.7
              11,682.3
              4,862.4
              -4,583.5Subtotal
              101.7
              85,663.3
              99,560.3
              53,001.4Total
      Underlying Properties (100%)Proved
      Developed Producing
              2,528.5
              281,012.0
              602,687.9
              340,591.5Proved
      Nonproducing
              31.8
              2,852.3
              7,307.6
              3,099.4Proved
      Undeveloped
              444.8
              39,380.7
              41,900.3
              -2,969.7TOTAL
              3,005.1
              323,245.0
              651,895.8
              340,721.2
  
 XTO
      Energy Inc.
                February
      17, 2010Page 2
  MLL
performed evaluations, which are designated as the SEC Pricing Case, using price
and expense premises specified by XTO and described in detail on Attachment
1.
 
 Proved
reserves and future net revenues were estimated in accordance with the
provisions contained in Securities and Exchange Commission Regulation S-X, Rule
4-10(a).  The Securities and Exchange Commission definition of proved
reserves is shown on Attachment 2.  Gas volumes for each property are
stated at the pressure and temperature bases appropriate for the sales contract
or state regulatory authority; therefore, some of the aggregated totals may be
stated at a mixed pressure base.  No provisions for the possible
consequences, if any, of product sales imbalances were included in our
projections since MLL received no relevant data.  Estimates of future
net revenues and discounted future net revenues are not intended and should not
be interpreted to represent fair market values for the estimated
reserves.  In MLL’s projections, future costs of abandoning facilities
and wells were assumed to be offset by salvage values.  Estimated
costs, if any, for restoration of producing properties to satisfy environmental
standards are beyond the scope of this assignment.
 
 Following
Attachment 2 is a list of exhibits that include annual projections of future
production and net revenues for each state and reserves
category.  Also included in the exhibits are one-line summaries for
the total royalty trust and for each state showing the proved reserves and
future net revenues for the individual properties.  Projections of
individual property future production and net revenues are included in separate
volumes to this report.  These exhibits and volumes should not be
relied upon independently of this narrative.
 
 The
proved developed producing reserves and production forecasts were estimated by
production decline extrapolations, water-oil ratio trends, P/Z declines, or in a
few cases, by volumetric calculations.  For some properties with
insufficient performance history to establish trends, MLL estimated future
production by analogy with other properties with similar
characteristics.  The past performance trends of many properties were
influenced by production curtailments, workovers, waterfloods, and/or infill
drilling.  Actual future production may require that MLL estimated
trends be significantly altered.
 
 The
estimated proved developed nonproducing reserves can be produced from existing
well bores but require capital costs for recompletions or for pipeline
connections.  These proved developed nonproducing reserves estimates
were based on analogies with other wells that commercially produce from the same
formation in the same field.  The timing of initial production was
provided to MLL by XTO.  When actual production history is available
for these nonproducing reserves, MLL’s reserves estimates may be significantly
revised.
  
 XTO
      Energy Inc.
                  February
      17, 2010Page 3
 The
estimated proved undeveloped reserves require significant capital expenditures,
such as for planned drilling and completion costs.  The proved
undeveloped reserves estimates for infill wells are based on analogies to
similar infill wells in the same field and/or the production histories of offset
wells in the same field.  As actual results of the planned drilling
become available, MLL’s reserves estimates may be significantly
revised.
 
 Reserves
estimates from volumetric calculations and from analogies are often less certain
than reserves estimates based on well performance obtained over a period during
which a substantial portion of the reserves was produced.
 
 The data
employed in MLL’s estimations of proved reserves and future net revenues were
provided by XTO.  The current expenses for each lease were obtained
from operating statements provided by XTO except for certain leases where XTO
deducted items considered by XTO to be nonrecurring expenditures.  No
overhead was included for those properties operated by XTO.  For some
properties, such as large waterfloods, XTO assumed a decline in operating costs
due to depleting production that was derived by forecasting a decrease in the
property well count.  For some gas properties, XTO assumed operating
costs would be split between a variable component and a fixed
component.  The variable component was a constant cost per thousand
cubic fee of gas production and the fixed component was a constant cost per well
completion.  Also, for some properties that XTO operates, operating
expenses were reduced due to contractual payments received from non-operators
that were greater than the non-operated working interest portion of the
expenses.  None of the data provided to MLL by XTO, including, but not
limited to, graphical representations and tabulations of past production
performance, well tests and pressures, ownership interests, prices, and
operating costs, were verified by us as such was not within the scope of MLL’s
assignment.
 
 The
evaluations presented in this report, with the exceptions of those parameters
specified by others, reflect MLL’s informed judgments based on accepted
standards of professional investigation but are subject to those generally
recognized uncertainties associated with interpretation of geological,
geophysical, and engineering information.  Government policies and
market conditions different from those employed in this study may cause the
total quantity of oil or gas to be recovered, actual production rates, prices
received, or operating and capital costs to vary from those presented in this
report.  Minor precision inconsistencies in subtotals may exist in the
report due to truncation or rounding of aggregate values.
 
 Miller
and Lents, Ltd. is an independent oil and gas consulting firm.  No
director, officer, or key employee of Miller and Lents, Ltd. has any financial
ownership in XTO Energy Inc. or any related company.  MLL’s
compensation for the required investigations and preparation of this report is
not contingent on the results obtained and reported, and we have not performed
other work that would affect our objectivity.  Preparation of this
report was supervised by an officer of Miller and Lents, Ltd., who is a
professionally qualified and licensed Professional Engineer in the State of
Texas with more than 25 years of relevant experience in the estimation,
assessment, and evaluation of oil and gas reserves.
  
 XTO
      Energy Inc.
                  February
      17, 2010Page 4
 MLL’s
work papers and data are in our files and available for review upon
request.  If you have any questions regarding the above, or if we can
be of further assistance, please call.
  Yours
      very truly,
                  
                  MILLER
      AND LENTS, LTD.
                    Texas Registered Engineering Firm No.
      F-1442By:
                /s/ James
      C. PearsonJames
      C. Pearson, P.E.Chairman
 
 JCP/slc
 
 
  Attachment
1
  
 
 
 12/31/09
 
 Cross
Timbers Royalty Trust (100%)
 
 SEC
PRICING CASE
 
 
 A.
              Oil
      Price
              Average
      price during the 12-month period prior to 12/31/09 determined as the
      arithmetical average of the first-day-of-the-month price for each month
      during the year 2009.  The average price was held constant
      through the life of the property.
 
 B.
              Gas/NGL
      Price
              Average
      price during the 12-month period prior to 12/31/09 determined as the
      arithmetical average of the first-day-of-the-month price for each month
      during the year 2009.  The average price was held constant
      through the life of the property.
 
 C.
              Operating
      Costs
              Current
      expenses held constant through the life of the property.  For
      some properties, expenses included a variable component that was a
      constant cost per unit of gas production and a fixed component that was a
      constant cost per well completion.
 D.
                Discount
      Rate
                10%
      per year.
  
  Attachment
2
 Page
1
  Reserves
Definitions In Accordance With
 Securities and Exchange
Commission Regulation S-X
 
 Reserves
 
 Reserves are estimated remaining
quantities of oil and gas and related substances anticipated to be economically
producible, as of a given date, by application of development projects to known
accumulations. In addition, there must exist, or there must be a reasonable
expectation that there will exist, the legal right to produce or a revenue
interest in the production, installed means of delivering oil and gas or related
substances to market, and all permits and financing required to implement the
project.
 
 Reserves should not be assigned to
adjacent reservoirs isolated by major, potentially sealing, faults until those
reservoirs are penetrated and evaluated as economically
producible.  Reserves should not be assigned to areas that are clearly
separated from a known accumulation by a non-productive reservoir (i.e., absence
of reservoir, structurally low reservoir, or negative test
results).  Such areas may contain prospective resources (i.e.,
potentially recoverable resources from undiscovered accumulations).
 
 
 Proved Oil and Gas
Reserves
 
 Proved oil and gas reserves are those
quantities of oil and gas, which, by analysis of geoscience and engineering
data, can be estimated with reasonable certainty to be economically
producible—from a given date forward, from known reservoirs, and under existing
economic conditions, operating methods, and government regulations—prior to the
time at which contracts providing the right to operate expire, unless evidence
indicates that renewal is reasonably certain, regardless of whether
deterministic or probabilistic methods are used for the
estimation.  The project to extract the hydrocarbons must have
commenced or the operator must be reasonably certain that it will commence the
project within a reasonable time.
 
 1.
              The
      area of the reservoir considered as proved
  includes:
 
 a.
              The
      area identified by drilling and limited by fluid contacts, if any,
      and
 
 b.
              Adjacent
      undrilled portions of the reservoir that can, with reasonable certainty,
      be judged to be continuous with it and to contain economically producible
      oil or gas on the basis of available geoscience and engineering
      data.
 
 2.
              In
      the absence of data on fluid contacts, proved quantities in a reservoir
      are limited by the lowest known hydrocarbons (LKH) as seen in a well
      penetration unless geoscience, engineering, or performance data and
      reliable technology establishes a lower contact with reasonable
      certainty.
 
 
 3.
              Where
      direct observation from well penetrations has defined a highest known oil
      (HKO) elevation and the potential exists for an associated gas cap, proved
      oil reserves may be assigned in the structurally higher portions of the
      reservoir only if geoscience, engineering, or performance data and
      reliable technology establish the higher contact with reasonable
      certainty.
 
 4.
              Reserves
      which can be produced economically through application of improved
      recovery techniques (including, but not limited to, fluid injection) are
      included in the proved classification
when:
 
 a.
              Successful
      testing by a pilot project in an area of the reservoir with properties no
      more favorable than in the reservoir as a whole, the operation of an
      installed program in the reservoir or an analogous reservoir, or other
      evidence using reliable technology establishes the reasonable certainty of
      the engineering analysis on which the project or program was based;
      and
 
 b.
              The
      project has been approved for development by all necessary parties and
      entities, including governmental
entities.
  
 Attachment
2
 Page
2
 5.
              Existing
      economic conditions include prices and costs at which economic
      producibility from a reservoir is to be determined. The price shall be the
      average price during the 12-month period prior to the ending date of the
      period covered by the report, determined as an unweighted arithmetic
      average of the first-day-of-the-month price for each month within such
      period, unless prices are defined by contractual arrangements, excluding
      escalations based upon future
conditions.
 
 
 Developed Oil and Gas
Reserves
 
 Developed oil and gas reserves are
reserves of any category that can be expected to be recovered:
 
 1.
              Through
      existing wells with existing equipment and operating methods or in which
      the cost of the required equipment is relatively minor compared to the
      cost of a new well; and
 
 2.
              Through
      installed extraction equipment and infrastructure operational at the time
      of the reserves estimate if the extraction is by means not involving a
      well.
 
 
 Undeveloped Oil and Gas
Reserves
 
 Undeveloped oil and gas reserves are
reserves of any category that are expected to be recovered from new wells on
undrilled acreage, or from existing wells where a relatively major expenditure
is required for recompletion.
 
 1.
              Reserves
      on undrilled acreage shall be limited to those directly offsetting
      development spacing areas that are reasonably certain of production when
      drilled, unless evidence using reliable technology exists that establishes
      reasonable certainty of economic producibility at greater
      distances.
 
 2.
              Undrilled
      locations can be classified as having undeveloped reserves only if a
      development plan has been adopted indicating that they are scheduled to be
      drilled within five years, unless the specific circumstances, justify a
      longer time.
 
 3.
              Under
      no circumstances shall estimates for undeveloped reserves be attributable
      to any acreage for which an application of fluid injection or other
      improved recovery technique is contemplated, unless such techniques have
      been proved effective by actual projects in the same reservoir or an
      analogous reservoir, as defined below, or by other evidence using reliable
      technology establishing reasonable
certainty.
 
 Analogous
Reservoir
 
 Analogous reservoirs, as used in
resources assessments, have similar rock and fluid properties, reservoir
conditions (depth, temperature, and pressure) and drive mechanisms, but are
typically at a more advanced stage of development than the reservoir of interest
and thus may provide concepts to assist in the interpretation of more limited
data and estimation of recovery. When used to support proved reserves, an
“analogous reservoir” refers to a reservoir that shares the following
characteristics with the reservoir of interest:
 
 1.
              Same
      geological formation (but not necessarily in pressure communication with
      the reservoir of interest);
  2.
              Same
      environment of deposition;
 
 3.
              Similar
      geological structure; and
 
 4.
              Same
      drive mechanism.
 
 Reservoir
      properties must, in aggregate, be no more favorable in the analog than in
      the reservoir of interest.