The Morrison Basin, which stretched from New Mexico in the south to Alberta and Saskatchewan in the north, was formed during the Nevadan orogeny, a precursor event to later orogenic episodes that created the Rocky Mountains started pushing up to the west. The deposits from their east-facing drainage basins, carried by streams and rivers from the Elko Highlands (along the borders of present-day Nevada and Utah) and deposited in swampy lowlands, lakes, river channels and floodplains, became the Morrison Formation.