to the National Atlas Home page
About | Fact Sheets | Contact Us | Partners | Products | Site Map | FAQ | Help | Follow us on Twitter 
Part of Project LogoAgricultureBiologyBoundariesClimateEnvironmentGeologyGovernmentHistoryMappingPeopleTransportationWater
to the Interactive Map MakerMap LayersPrintable MapsWall MapsDynamic MapsArticlesMapping Professionals

Map Maker
Geologic Map
Shaded Relief
Map Layer
Generalized Geologic Map of the Conterminous United States
North America Shaded Relief


  The North American Tapestry of Time and Terrain

The Two Maps
Zoom In
Legend and Rock Ages
Rock Types
Political Boundaries


Rocky Mountains

  Close-up of
 the Rocky Mountain region
The late Cretaceous and early Tertiary periods were geologically eventful in western North America. The Rocky Mountains, which rose about 50 to 100 million years ago, extend from southern Colorado northwest into Canada. Their rocks and topography are diverse and highly complex. Many of the individual ranges that make up the Rocky Mountains appear on the map as variously shaped bull's-eyes surrounding a red-hued center. Each crude, ringed pattern was created by the erosion of overlying Paleozoic and Mesozoic sedimentary rocks during the Tertiary period. This erosion has revealed a core of uplifted Precambrian granite.