If I'm reading the book right, it appears that the Survival skill is useless (or nearly so) to Space Marines. This seems odd to me, especially since many Space Wolves and Storm Wardens (among others) should have it. I also noticed that the CSMs from The Emperor Protects all have Survival, many at +10. Seems odd for them to focus on it if it's really that useless.
I'm considering just adding Survival to the list of starting Skills for all Astartes. It's not like they couldn't have had need for it and picked it up as Scouts. If it's almost useless, i just can't see charging 300 xp for it.