Fossils with beautiful full-colour description! Packed with 10 pieces sorted.

Fossils are all remains and traces of plants and animals that are preserved in rock. Contrary to popular belief, fossils do not necessarily require 'petrification'. Very many fossils are indeed not petrified. Even from very old rocks, fossil remains are known that have hardly changed. Furthermore, many people think that fossils are always very old. This is also incorrect. Many very young fossils are known, formed in periods known to humans. The science that studies fossils is called palaeontology. This field of knowledge helps in the research of the succession of rocks, a branch of geology called biostratigraphy. Because remains of life only fossilise under specific circumstances, fossil information is limited and by definition "incomplete". When we think of the word fossil, we often think of the bones of dinosaurs or mammoths, and it is indeed true that the hard parts of an organism have the greatest chance of being preserved by fossilisation. For vertebrates, these are the bones and especially the teeth. The softer tissues of the organism are only preserved in special cases and are therefore much rarer. Softer tissues are only preserved if they are quickly buried under a layer that protects them from any form of rotting or grazing. With only the hard parts, it is sometimes difficult to form a good picture of the complete organism. A good example of this is the Conodonta, which were found in large numbers for a long time but were only known from their teeth. It was only when an impression of the rest of such an animal was found that it turned out to be a primitive form of the phylum Chordata. In other animal groups, other hard parts, such as shells, are often fossilised. There are a number of special forms of fossilisation. For example, complete insects are sometimes enclosed in amber because the resin from which the amber is formed forms a good seal against oxidation. This also applies on a larger scale to tar pits. Near the American city of Los Angeles, a good example of this is the La Brea Tar Pits. The bones of animals that became trapped in the tar pit were often exceptionally well preserved. In addition, the trapped animals often attracted predators, which also became entangled. In this way, a "bone graveyard" was formed during the Pleistocene. Very well-preserved fossils are often found in clays that were deposited in stagnant, oxygen-free water. Due to the absence of oxygen, plants fossilise particularly well in this. Very often, not the entire water column is oxygen-free, but only the lower part. Such stratified water therefore has a normal oxygen content in the upper layer. Organisms die in the upper layer and then sink down and end up in an oxygen-free environment where they are preserved. Living organisms can also unintentionally end up in the lower oxygen-free layer, causing them to die and fossilise. In such a deposit, fish are sometimes preserved in a cramped manner, which indicates suffocation. A well-known rock with such fossils is the 'Kupferschiefer' from Rotliegend in Central Germany. In addition to remains that originate from organisms themselves, traces that have been actively or passively made by organisms are also considered fossils. These include, for example, coprolites (fossilised excrement) and trace fossils such as footprints and burrows. It is not always possible to determine which animal trace fossils originate from. Therefore, they often receive their own taxonomic name.