Browse Items (155 total)

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Thumbnail for insect fossil video

This chart shows the way geologic time is broken down into smaller spans of time called Eons, Eras, Periods, and Epochs. The top of the chart is current time, labeled as 0 Ma (0 years before present). The bottom of the chart represents the beginning…

(no number) Preserved ivory varies widely in appearance from one site to the next, but the tusk itself can easily be mistaken for petrified wood because it forms concentric rings as the animal grows. Tusk fragments are generally thin, with a slight…

Thumbnail of Fossilization Video

(DSM #10565) This brachiopod has had its shell partially replaced by the mineral pyrite. Pyrite is also known as fool's gold.

(DSM #M410) This Turritellid snail has been completely replaced with the mineral pyrite. Some pyrite nodules have also begun to form and grow.

(unnumbered) Petrified wood often exhibits a combination of replacement and permineralization. This specimen clearly shows how the cell walls have been replaced with minerals. The cells themselves are also filled in some cases.

(DSM #PL58) This section of palm wood very clearly shows how individual cells of an organism can be filled with minerals in the process of permineralization.

(unnumbered) Compression fossils most often form in sedimentary rocks called shales which form in the bottom of lake or sea beds. The same fossil can be seen in both the part and counterpart but different features are often preserved on both sides.…