In September 1950, Metzler (P) and Bolen (D) defendant entered into a contract for deed whereby D agreed to sell, and P agreed to purchase, the northeast quarter of section 25 in township 155 north of range 95 west of the 5th principal meridian in Williams County. The agreement was in the usual form, except as to the following provision which was typed therein by E. C. Rudolph (attorney for plaintiff) prior to the execution thereof: 'The second party herein shall have unto himself 6 1/2% of 50% of oils, metals, minerals found in, under, or upon said land herein described, but he agrees to join with first party, on the same terms as he (1st party) accepts drilling rights given to any drilling Co., which first party selects.' The 'second party' referred to therein is P. P and D had communicated with each other, over a period of years, concerning the purchase or rental by P of the land. P sued in his suit claimed that 'That said provision in said Contract for Deed did not express the true Agreement between the P and D; that the agreement between the P and D was that D would convey to P all surface rights and an undivided fifty percent (50%) interest in and to all the oil, gas, metals and other minerals that D owned in the land described in this Complaint and said Contract for Deed; that at the time said Agreement was entered into it was believed mistakenly by the party preparing the Contract for Deed to be the fact that Williams County owned 50% of the oil, gas, metals and other minerals in said land.', and 'That said Contract for Deed through and by a mistake of fact does not express the true agreement between the parties to said Contract for Deed.' P prayed for specific performance of the alleged agreement by the execution and delivery of a warranty deed conveying said premises, including 50% of all of the oil, gas, metals and other minerals therein, for damages, and, in the event specific performance is not granted, judgment in the sum of $30,800, together with costs and disbursements. D admitted the execution and delivery of the Contract for Deed, admits receipt of all monies to be paid under the Contract but denied all other allegations of the Complaint. When the contract was executed both parties believed that Williams County did own 50% of all of the oil, gas and minerals in and under said land. However, on March 21, 1951, the Supreme Court of North Dakota, in the cases of Kershaw v. Burleigh County, 77 N.D. 932, 47 N.W.2d 132, and Kopplin v. Burleigh County, 77 N.D. 942, 47 N.W.2d 137, decided that such reservation was void, and that the tax deed from the County to the purchaser conveyed all right, title and interest of the County to the premises involved. Therefore, D was actually the owner of all of the oil, gas and minerals in and under said premises. The sole question involved herein is whether, because of such mistaken belief on the part of both parties to the Contract concerning the extent of D's interest in said oil, gas and minerals, plaintiff is entitled to the relief asked for.