The validity and effect of a testamentary disposition of real property, situated within the Virgin Islands, or of an interest in real property so situated, which would descend to the heir of an intestate, and the manner in which such property or such an interest descends, where it is not disposed of by will, are regulated by the laws of the Virgin Islands, without regard to the residence of the decedent. Except where special provision is otherwise made by law, the validity and effect of a testamentary disposition of any other property situated within the Territory, and the ownership and disposition of such property, where it is not disposed of by will, are regulated by the laws of the State or country, of which the decedent was a resident, at the time of his death. Whenever a decedent, being a citizen of the United States or a citizen or a subject of a foreign country, wherever resident, shall have declared in his will and testament that he elects that such testamentary dispositions shall be construed and regulated by the laws of this Territory, the validity and effect of such dispositions shall be determined by such laws.