Tex. Nat. Res. Code § 11.043

After payment of the amount due to the permanent school fund for proceeds from the sale of the portion of the public land set aside for payment of the public debt by act of the legislature in 1879 and payment directed to be made to the permanent school and university funds by act of the legislature in 1883, the remainder of the land not to exceed two million acres or the proceeds from their sale shall be divided in half and one of the halves shall constitute a permanent endowment fund for The University of Texas System.