Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio.
an area of about 2,000,000 sq mi (5,179,980 sq km) of Precambrian strata, consisting largely of granite, gneiss, marble, and other igneous and metamorphic rocks that occupy most of eastern and central Canada & part of NE U.S.
Used by arrangement with John Wiley & Sons, Inc.
The American Heritage® Dictionary of the English Language, 4th edition Copyright © 2010 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
See Laurentian Plateau.