A release of a deed of trust may be written by the trustee upon the record in the office of the clerk of the circuit court for the county where the deed of trust to be released is recorded and attested by the clerk of the court; and the clerk at the time of recording each deed of trust shall leave a blank space at the foot thereof for the purpose of entering such release. (Mont. Co. Code 1965, § 8-3; 1927, ch. 493, § 185.)