Back In Time

Looking through the view master at prehistoric animals.
"Does this brontothere still exist?"
"Well, when I was reading in Conversations With God, he was talking about how everything that Ever Existed still exists, same as everything that Will Ever Be is existing now. That time is not on a continuum, as is our thinking and experience, but that it's really stacked on top of eachother, like different planes." (much like Stephen Hawking's theories)
"I knew it! So they do exist."
"I'm thinking yeah, you were right." (which thought I always entertained, anyway.)
"So how can we find the creatures? How can we get there?"
"Well, we'd have to build some sort of space and time machine."
"Okay. Here's what we do. We go to Mars. In a rocket. Then we find a time scroll. Then we blast back here in the rocket, and set up the time scroll. We go back in time and save the animals. I want to bring back a ptera-bird. And a tyrranosaurus. And the saber tooth cat."
"What about the brontothere?" I ask, as I'm fond of the strange creature.
"Of course we'll rescue the brontothere. It's a vegetarian. We can't just let it go into extinction!"