This view out the window of a plane shows a gigantic fold in Dinosaur National Monument.
The rocks are part of the Split Mountain anticline. Just guessing, but its name might well be because it looks like the mountain has been split in half.
An anticline is a type of fold. In this case, older rocks form the core of the structure while younger rocks form the outer edges. The rocks were pushed upwards, which can stretch and break the rocks at the hinge of the fold, making them weaker and easier to erode.
The rocks on the outer edges of this anticline are sandstones that are fairly resistant to erosion, while older rocks in the middle are more easily eroded. Once the outer sandstone layers were fractured at the fold hinge, they eroded away and exposed the more easily eroded layers at the core. The unfractured rocks away from the hinge still stand tall, creating the two limbs of the mountains.
This anticline also is a plunging anticline. You see it literally is disappearing towards the right side of this image; the fold is pushed upwards much more in the left side of the shot than in the right.