When this Constitution shall go into effect, the books, records, papers, and proceedings of the probate court in each county, and all causes and matters of administration and guardianship, and other matters pending therein, shall be transferred to the county court of such county, except of Day County, which shall be transferred to the county court of Ellis County, and the county courts of the respective counties shall proceed to final decree or judgment, order, or other termination in the said several matters and causes as the said probate court might have done if this Constitution had not been adopted. The District Court of any county, the successor of the United States Court for the Indian Territory, in each of the counties formed in whole or in part in the Indian Territory, shall transfer to the county court of such county all matters, proceedings, records, books, papers, and documents appertaining to all causes or proceedings relating to estates: Provided, That the Legislature may provide for the transfer of any of said matters and causes to another county than herein prescribed.