Originally posted by BloodRain
Neme you know your stuff here. Was it the gravity-fall itself that created that quote, or is that the events of the battle before the defeat-fall?
I'd say the latter, more or less. The Silmarillion itself makes no mention of Ancalagon's fall destroying more than the three mountains.
"Thus, an end was made of the power of Angband in the North, and the evil realm was brought to naught; and out of hope into the light of day, and they looked upon a world that was changed. For so great was the fury of those adversaries that the northern regions of the western world were rent asunder, and the sea roared in through many chasms, and there was confusion and great noise; and rivers perished or found new pathsm and the valleys were upheaved and the hills trod down; and Sirion (a river) was no more."
This is what my copy of The Silmarillion says, and note it attributes the destruction to no one being, but "adversaries". This leads me to believe that it was a prolonged effect, done by many individuals. Indeed, Ancalagon was but one of the mighty creatures who fought in the War of Wrath (And probably the most powerful). There were Maiar (Demigods), powerful First Age Elves (Some like Galadriel are proven town busters), and other dragons there.
Ancalagon is really big and the most powerful dragon to ever exist, sure, but he is nothing compared to the Juubi.