Peak Eruption can target any land with the subtype Mountain, not just those named Mountain. It can't target a land that doesn't have that subtype, even if the land can tap for {R}.
15-09-2013
wotc
If the target Mountain is an illegal target when Peak Eruption tries to resolve, it won't resolve and none of its effects will happen. No damage will be dealt. However, if Peak Eruption resolves and the Mountain isn't destroyed (perhaps because it has indestructible), damage will be dealt.
Random a card of Magic: The Gathering (MTG), but you can also roll the D20 dice, random a Planeswalker, have fun with the random rules and more.
Adam Paquette2013-09-27
