Title text:
Even geology papers about Heart Mountain are like, "Look, we all agree this 'volcanic gas earthquake hovercraft' thing seems like it can't possibly be right, but..."
Transcript:
Transcript will show once it’s been added to explainxkcd.com
Source: https://xkcd.com/3162/
The Ordovician period was 485.4 to 443.8 million years ago, so there may have been fossils in that layer that were long dead and turned to stone 400 millions years earlier than the slip, and then another 50 million years after that, there are modern humans speculating about the cause of this slippage.
I sort of get why some people are attracted to creationist beliefs about earth being only 6000 years old. Those time spans are dizzying to think about.