A great site with plenty of pix on the brother and sister team of Fanchon and Marco, put together by a son, is
here
A good single page on F&M is
here
They gave a start to Cyd Charisse (age 12) Joan Crawford, Martha Raye, Johnny Downs, Janet Gaynor, Dorothy LaMour, Judy Garland (Gumm Sisters), Doris Day, Bing Crosby, etc
Fanny (Franchon) and Mike (Marco)
www.fanchonandmarco.com
Fanchon's husband, Wm Simon, Sr, founded Simon's Drive-ins.