Hints: fern horsetails club mosses fossil Scottish Carboniferous Meganeura wingspan millipede cockroach 音频缺失 最后一词为undergrowth

This was no ordinary forest. What looked like trees were in fact giant ferns, horsetails and club mosses, the fossils of which have been exquisitely preserved in this Scottish park. They offer a glimpse of the botanic wonders that once filled Europe's ancient forests. These club mosses grew a massive 13 meters tall.
Long before birds appeared on the planet, these Carboniferous forests would have echoed to a very different dawn chorus.
Predatory dragonflies were common, and some were absolutely huge. This one, Meganeura, was the size of a hawk, with a wingspan of over 60 centimeters. The forest floor was a bug's world too. Fossil footprints of a millipede show that it was nearly two meters long. Over 800 species of cockroach scurried through the ancient undergrowth.

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