Originally Posted by
nvubu
It definitely isn't a mark on the film as it appears on a number of other images I have. Here is it at full resolution from the image. No idea what the cross is either.
But they don't appear today - although there is something where the X was - and this GE image has some sort of crop shadow where the seahorse is/was.
y
Probably a local low that collected water and drained down the channel. After 60 years its been reduced in size but not eliminated