Inversion in relative clause

The gardens stretched back to some reasonable-looking pasture land on which grazed a few cattle and sheep.

Why is this inversion valid here? I would expect maybe "on which there grazed" (as in "there comes a time") if an inversion were to be happen.

Solution 1:

Subject-Verb Inversion

1. After expression of "some place"

Five beach umbrellas were on the beach.

On the beach were five beach umbrellas.

In front of the house stood some giant trees.

To the north is the stream that the settlers will have to ford.

2. After "no not never"

Not once did I miss a question.

Never had I seen such a glorious sight.

On no occasion did they say that to me.

No sooner had we entered the hall than the ceremony began.

Nowhere did he see her.

At no time did he go out of the house.

3. After "rarely, hardly, scarcely, not only, barely, only, seldom, little"

Seldom has their secretary made such mistakes.

Only after he saw her did he understand.

Rarely had he finished the exam when the teacher collected the papers.

4. After "so, neither, nor" So happy was she that she danced around the room.

I liked the coffee, and so did Mike.

I was born in Seoul. So was my father.

5. When if is omitted in conditionals

If he had seen you, he would have greeted you.(Had he seen you, ~.)

If anything should happen in my absence, ask him.(Should anything happen in my absence, ~.)

If it were not for the sun, nothing could live.(Were it not for the sun, ~.)

Source: One of my TOEFL books.