Every supervisor of a township, upon receiving the lists and forms as aforesaid, shall proceed to estimate and appraise the value of all the improvements upon the several tracts or parcels of land mentioned in such lists, and after making such appraisement according to the forms prescribed by said commissioner, he shall make returns thereof duly certified by him to the commissioner, on or before the first day of August in the same year: Provided, That the provisions of this section shall not apply to any settler mentioned in or contemplated by the “Act to provide for the sale of certain lands to the settlers thereon, and for other purposes,” approved March twenty-fifth, 1840, and the several acts amendatory thereof, whose lands have been forfeited to this state, or who has not become a purchaser of the lands on which he resides, and on which his settlement is made, nor shall it apply to any person who has made, or who hereafter may make improvements on any of the university, school or state building lands; and who shall hereafter become a purchaser of the same. But such settler or other person shall be entitled to enter the same upon the terms herein established for the sale of unimproved university lands, irrespective of the value of said improvements, and he shall not be chargeable for the value of said improvements so made by or assigned to him.