The 1995 western North American Deep Probe seismic experiment, a continental-scale, long-range refraction investigation, extended form the Colorado Plateau to the Archean craton in Canada. The profile crossed the Proterozoic terranes of the Archean Wyoming province - a region modified by Phanerozoic tectonism, and the northern part of the Wyoming province and the Archean Hearne province - a region that has been relatively stable since the Archean. Each geologic province has a distinctive crustal type, that of the Wyoming province being the thickest and fastest. In the mantle, the change from low to high upper-mantle seismic velocity that marks the passage from the orogenic plateau to the craton in published teleseismic tomographic images is seen to occur abruptly in the vicinity of the Cheyenne belt, which separates the Proterozoic Rocky Mountain terranes form the Archean Wyoming province. To the south, the upper mantle beneath the southern Rocky Mountains has a well-developed P-wave low-velocity zone like that beneath the Gulf of California spreading system. To the north, the upper mantle beneath the Archean provinces resembles the teleseismic average for the Canadian shield.