(case involves decedent's 1955 holographic will (decedent died in 1965) which devised 158 acres to each of the decedent's three sons and stated that the three sons were to "share and share alike production royalty and unproduction royalty"; court reverse trial court and holds that decedent devised each son a separate tract of land together with all mineral rights and interests beneath the respective tract, except for royalties and shut-in royalties paid or to be paid on any well on any of the land devised under the will (which are to be shared under the will)).