I can’t say, but I think I remember being taught that organic matter could not survive that long. However, that was a long time ago (but of course, not long enough for me to have fossilized—quite).
“organic matter”
“Dr Wilby, who led the excavation, said: “We think that these creatures were swimming around during the Jurassic period and were turned to stone soon after death. It’s called the Medusa effect.”
“turned to STONE”
So they reconstituted the fossilized “ink” with a liquid, and drew the picture. This is being completely misconstrued! It was STONE!
Oh, you could fossilize quite quickly. Just takes the right conditions like a very quick burial. Flood perhaps.
Science makes a lot of assumptions. Dates are one of them.