You may be thinking of the Trans-Antarctic mountains.
That would be the Himalayan chain of mountains.
Appalachian Mountains (oldest in US)
Mid-Atlantic chain
a mountain range
the hee hee
Canmore
The collective nouns for mountains are a chain of mountains or a range of mountains.
The Dublin Mountains, which are just the northern fringe of the Wicklow Mountains.
The chain of mountains in the northeast of Spain are the Pyrenees.
The Rocky mountains.
The Himalaya Mountains :D
Appalachian mountains