Newfoundland in the Early Ordovician (490 million years ago) and
Subduction of the Iapetus Ocean caused the slow collision of Laurentia and
Gondwana, forming a huge new continent. Across the middle of the
continent, where the Iapetus Ocean had once been, there was a mountain
range, and half way along this lay what is now Newfoundland. About 200
million years ago, this continent broke apart to form the present Atlantic
Ocean; the fracture, however, occurred slightly to the east of the earlier
collision line, leaving fragments of Gondwana still attached to Laurentia.
The Eastern Zone of Newfoundland is one of these fragments.
From Stephen Colman-Sadd and Susan A. Scott,
Newfoundland and Labrador: Travellers Guide to the Geology
(St. John's: Government of Newfoundland and Labrador, 1994).