The Book Cliffs are these incredible sand and stone cliffs rising on the north side of the Grand Valley, north of Grand Junction. The escarpment that rises to the south of Grand Junction and creates the landscape of the Colorado National Monument (part of the Uncompahgre Uplift, which is part of the Colorado Plateau) is created by a fault line running east and west at the northern edge of that uplift. What created the Book Cliffs, I don't know, but if there's another fault line over here, it makes the Grand Valley look like a fault-block valley.
The top of the Book Cliff escarpment is a multi-colored solid rock cliff with bands of sand and maybe volcanic ash sloping away below. These lower slopes have a lot of what looks to be monuments of more solid material rising through the softer sands. There's also quite a bit of hard rockfall in these lower slopes.
The I-70 emerges from the Colorado River Canyon just east of Clifton and runs westward along the lower edges of the sandy slopes. Grand Junction itself is several miles south of these cliffs.
Monuments rising through the heavily eroded sand slopes
Notice the boulders that have fallen from the upper cliffs
This promontory rises near the beginning of the Colorado River Canyon, east of Clifton