Cecil frowned. That was a contradiction. ...And also a long time ago. Wow.

"Well," he said slowly, "Maybe... maybe the tapes were also from before the cataclysm! Or based, perhaps, on prior knowledge that people more interested in the topic than I am have, that I do not. Maybe they were on loan from this museum, even. Or..." He considered briefly. "Maybe... maybe our timelines are not exactly equivalent. Maybe there existed months or years here, which time in your own world is not able to account for."

He made a wiggling motion with one hand, to indicate uncertainty. "Measuring time before and immediately following the cataclysm is a little.... eeeehhh. You know?"