Everything is possible. Previous friends came from the definition, but in reality, the shape of the mountain is ever-changing, so it must be a standard cone. (Unless artificially piled, there are few natural cones, but there are many volcanic cones, such as Mount Fuji).
The mountain in reality may be an arc, and there is only one main peak, so the place where the mountain is included is the valley. For example, a person sits on the ground with his legs apart and his hands on it. If the mountain shape is like this, his head is the main peak, and the area surrounded by his hands and legs can also be a valley.
This is also the case in Guizhou. There is a crack in the middle of a good mountain (but it does not run through the whole mountain), so this crack is also a valley, the so-called rift valley, similar to the sky.
In ancient times, there was another situation. For example, a mountain, which had a good shape, was dug at the foot, that is, a conical mountain was dug at the foot of the mountain to form an artificial valley, which is often a place with excellent feng shui.
If the landlord is free, he can go out and see more, climb mountains and hike, and see more actual mountain shapes. Maybe you will have an answer to this question yourself.