The defendant nephew and his wife purchased a quarter section of farm land from his aunt (deceased in 1999) and uncle under an agreement for sale. The plaintiff executors contended the statutory requirements for a severance were met by virtue of the Tessiers' mutual consent to the sale of the land and registration of the caveat. A trial of an issue was directed to determine whether that agreement severed the joint tenancy and to determine who was entitled to receive the remaining payments under the agreement for sale. The issues of accounting for payments and balance owing under the agreement were resolved in advance of the trial. Yvonne's 1997 Will, for which letters probate issued in 1999, made no specific reference to the land in question.HELD: One-half of the outstanding proceeds under the agreement for sale were payable to Yvonne's estate from the date of her death. 1)The joint tenancy was severed in 1996 when the owners mutually agreed to sell. They agreed each would receive one-half of the purchase price. Those payments were maintained in separate bank accounts. Taken together, these are sufficient indicia of the destruction of the unities of interest and possession both by agreement and course of conduct. The Tessiers held their interest and proceeds of the sale as tenants in common thereafter. 2)The two distinguishing features of a joint tenancy are the right of survivorship and the four unities of title, interest, possession and time. The unity of time of vesting only applies to the original creation of the joint tenancy and cannot be affected by any subsequent act. The destruction of any of the three remaining unities severs the joint tenancy and creates a tenancy in common. 3)Section 240 of the Land Titles Act is not intended to expand upon these common law ways of severing a joint tenancy. The section is designed to limit the unilateral alienation of the interest of one joint tenant vis a vis another joint tenant. Ascertaining whether or not a joint tenancy has been severed by mutual disposition by all joint tenants and destruction of one or more of the three unities is a question of fact. 4)Parol evidence is not admissible if the agreement is both clear and unambiguous. Other evidence should not be admitted to alter or vary the written words. Parol evidence to the effect there was no intention to severe the joint tenancy directly contradicted the agreement and subsequent conduct of equally splitting all proceeds from the sale in the 2 years preceding Yvonne Tessier's death. 5)Rectification was not ordered. There was no mutual mistake. There was no evidence which left a 'fair and reasonable doubt' that the agreement did not embody the final intention of the parties. Had either intended to benefit the other on death they could and should have embodied that intention in their testamentary dispositions. 6)If a collateral contract existed between Mr. and Mrs. Tessier, it was entirely oral and was not supported by any documentary evidence including their Wills and could be proven only by the parol evidence of both.