The Canadian Shield is a massive U-shaped chunk of central and eastern Canada that includes Labrador, most of Quebec, most of Ontario, half of Saskatchewan, and most of Nunavut—8 million square kilometers in all. Although a portion of it dips into the US Great Lakes states, it’s pretty much a Canadian thing, comprising rock that bubbled forth billions of years ago. It was the first part of North America to be permanently elevated above sea level and, ever since, it has been essentially untouched by encroachments of the oceans.

Go Shield!
(from Souvenir of Canada 2, by Douglas Coupland)