This chapter shall not be applied to bar the rights of any lessor or his successor as reversionary of his right to possession on the expiration of any lease by reason of failure to file the notice herein required, the rights of any remainderman upon the expiration of any life estate or trust created within twenty-three years prior to the date of an affidavit made and recorded as prescribed by § 43-30-7, right founded upon any mortgage, trust deed, or contract for sale of lands which is not barred by the statute of limitation, or conditions subsequent in any deed.
SDCL 43-30-12