Lost Chao Locations
Locating the Ancient Ruins:
When you get to the part with the caged Phoenix, and the third checkpoint - stop there and look to the left for a platform that will take you down off the edge. It will lead to a lower platform where the Ancient Ruins are.
Finding the Lost Chao:
Activate the ruins with the Mystic Melody and a teleporter will appear right above it. Enter the teleporter and it will take you to an area where you can see a series of platforms and the Lost Chao in the distance. Hover across to each platform, being careful of the G.U.N. robots stationed there including one guarding the Lost Chao itself!