San Gabriel Blvd. over the Rio Hondo north of Paso de Bartolo
This is northward view of the Rio Hondo with San Gabriel Blvd. passing over. The photo says that it is "Mission Road" but there is no such street in the Paso de Bartolo or Portero Chico or Portero Grande. Contemporary maps show a tight bend in the Rio Hondo north of the Paso de Bartolo where San Gabriel Blvd. crosses. Further there was plenty of oil production in the 1920's (it is still there now).
Photo taken by Spence Air Plane Photos (Los Angeles)