exhibit 10. 7 assignment and assumption of leases this assignment and assumption of leases ( this “ assignment ” ) is made as of february 28, 2008 ( the “ effective date ” ), by and between chesapeake energy corporation, an oklahoma corporation ( “ assignor ” ), and quest resource corporation, a nevada corporation ( “ assignee ” ). r e c i t a l s : a. assignor, as the successor - in - interest to ricks exploration, inc. ( “ ricks ” ), holds a leasehold interest pursuant to that certain lease agreement dated april 8, 1998, between teachers insurance and annuity association of america, as landlord, and ricks, as tenant, as amended by that certain amendment no. one to lease agreement dated as of september 25, 1998 and amendment no. two to lease agreement dated as of march 15, 2001, ( as amended, the “ lease ” ), in certain premises consisting of 18, 684 square feet of space located on the 30th floor of the oklahoma tower, 210 park avenue, oklahoma city, oklahoma ( the “ leased premises ” ), as more particularly described in the lease which is attached hereto as exhibit a and made a part hereof. b. assignor is also the successor - in - interest to ricks in that certain sublease agreement dated march 14, 2003, between ricks, as sublandlord, and 3100 city place, l. l. c., as subtenant, as amended by that certain sublease amendment # 1 dated april 8, 2004 ( as amended, the “ city place sublease ” ), which is attached hereto as exhibit b and made a part hereof. c. assignor is also the successor - in - interest to ricks in that certain sublease agreement dated july 9, 2004, between ricks, as sublandlord, and crusader energy corporation, as subtenant ( as amended, the “ crusader sublease ” ), which is attached hereto as exhibit c and made a part hereof. collectively, the city place sublease and crusader sublease are hereinafter referred to as the “ subleases. ” d. assignor desires to sell, assign, transfer and convey to assignee, and assignee desires to obtain, all of assignor ’ s interest as ( i ) tenant in and to the lease and ( ii ) sublandlord in