U.S. District Judge Bruce S. Jenkins is considering a motion to dismiss two main plaintiffs in a suit involving the polygamist community of Colorado City, Ariz.

Defendants in the case argued Thursday that the statute of limitations has run out for a father and son who left the group, Harold and James Blackmore.Damian C. Smith, lawyer for the United Effort Plan, said the older Blackmore gave up his financial interest in the plan when he accepted a settlement of claims and left the community in 1967. In 1964, he conveyed Canadian property worth $150,000, which came under the plan's control.

In addition, Smith said, in 1976 Harold Blackmore signed a waiver settling all claims and promising not to sue. But now he not only has sued, but he has financed the suit of at least 15 of the 35 plaintiffs, he said.

Smith said James Blackmore was "kicked out" of Colorado City in 1975. So the statute of limitations, which could be no longer than four years, began running at that time, he said.

Jeffrey C. Swinton, representing the plaintiffs, said that fraud was involved in the 1964 conveyance and that it was discovered only last year.

He said Harold Blackmore retained an interest in the United Effort Plan - the value of the property given in 1964 minus the $7,000 settlement he later received.