According to this report, scientists are examining an area of Madagascar near Faux Cap for evidence that a megatsunami, a giant wave likely caused by an asteroid or comet impact, struct the area several thousand years ago. Using Google Earth, I found what appeared to be shore dunelike traces in that area that extend 20 miles in the northwest direction.

Note also the number of white indentations that point in the same direction.

Unfortunately, the picture was lost.