SDCL § 59-3-6: Agent's necessary authority--Representation as to matter of fact.

An agent has authority to make a representation respecting any matter of fact, not including the terms of his authority, but upon which his right to use his authority depends, and the truth of which cannot be determined by the use of reasonable diligence on the part of the person to whom the representation is made.

See Cal Civ Code, § 2319.