tuolumne meadows to the valley

You are not supposed to build new fire rings, but a lot of people ignore that rule. The result is that there are fire rings EVERYWHERE.
So chances are that if you think a particular spot looks attractive for camping, somebody in the past thought the same and built you a fire ring. Enjoy!

PS. Fires are prohibited above 9600 feet, so camp below that altitude if you want to have a fire.

Are there any legal ones?

People like to build fire rings out of rocks every time they have a fire. I really don't understand why.
If you are going to build a campfire in an area where people camp often, then use the fire ring. But if there isn't a fire ring, then just build it right on the ground and scatter your ashes when done. Whenever I see a fire ring while hiking off trail I always disassemble it.

Yup, below 9600 feet they are legal.

"But if there isn't a fire ring, then just build it right on the ground and scatter your ashes when done. Whenever I see a fire ring while hiking off trail I always disassemble it."

Or don't build a fire at all. I think we've built about three fires in the last seven years…always in an existing ring. You don't need a fire to camp, and they do mar the wilderness.