Newfoundland in the Early Ordovician (490 million years ago) and Newfoundland today.
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).