My favorite bit of the exchange:
[Pop Matters:] Time travel: where, when, and why?
[OS:] I would go back 300 million years or so, for I have always longed to see the earth in its Carboniferous age, long before mammals evolved, or even flowering plants. The planet was the domain of gymnosperms, non-flowering plants, then. There were ferns and tree ferns, and giant Calamites—segmented relatives of today’s horsetails, ten- or 20-meters high. There were huge Lepidodendron, a meter and a half in diameter, related to today’s tiny club mosses. And there were cycads, very similar to those that survive today.