Avsnitt 4

"The Rare Glimpses", examines areas of the fossil record where information is sparse. We visit The Burgess Shales in British Columbia, Canada where there's a rare deposit of soft-bodied animals, the sort that don't usually fossilize. The animals of The Burgess Shale are beautiful, unlikely and bizarre. The most common creatures preserved 500 million years ago, were trilobites . But what did the trilobites eat and what ate the trilobites? The creatures that trilobites preyed upon and those that preyed upon trilobites are found here, at The Burgess Shale. After the time of the dinosaurs, there's another period when small, delicate mammals only rarely fossilized and we see a rare glimpse of them at sites in Germany: one where the famous Archaeopteryx fossil was discovered and another where the mudstone is a mere 48 million years old and hasn't finished solidifying into rock.