From The Geology of the Great Basin by Bill Fiero, 1986

I know, this book is rather dated, but it is the only book available on the subject at Needles Branch library. :>(

The Great Basin resembles an upside-down, broken, and cracked bowl. No surface water leaves the Great Basin except by evaporation. Biologist and anthropologist have confused the usage of the term "Great Basin" by utilizing other criteria to define Great Basin biota or cultures, but the definition of the geographic region is founded only on hydrology.

Geologic province - the Basin and Range
The Basin and Range can be differentiated from its neighboring geologic regions by its uplifted and tilted ranges separated by broad elongated basins.

The hydrologic Great Basin, then, is that portion of the geologic Basin and Range with no drainage to the sea. The two great rivers of the West, the Colorado and Columbia, are gnawing away at the flanks.

In fact, the boundaries of the geologic Basin and Range do not exactly coincide with the hydrologic Great Basin. There are slight variations along all the borders except the southern edge. Here the Great Basin and Basin and Range boundaries are sharply divergent. The Colorado River has managed to slice across the trend of the Basin and Range, and the northward-reaching tributaries deeply incise the southern boundary of the Great Basin.

The neighboring geologic provinces are sharply contrasted to the tilted and topsy-turvy basin-and-range geology. To the north, young lavas of the Snake River Plain buried the Basin and Range beneath thousands of feet of almost horizontal effusives. The black flows poured southward into northern Nevada.

The Colorado Plateau bounds the Basin and Range to the east. This is a geologically stable region of brightly hued rocks that have recently been uplifted vertically almost one mile with virtually no deformation of the horizontal layers. Rivers have deeply incised the uplifted Colorado Plateau into some of the most scenic canyons in the United States. Many have been designated as national parks. This is the domain of Grand Canyon, Bryce Canyon, and Zion. To the south, the Basin and Range merges into the mountainous structures of central Mexico. To the west of the Basin and Range lies the Sierra Nevada geologic province. This province is characterized by massive intrusions of once-molten rock that has cooled into the tough, erosion-resistant core of the Sierras.