3-4 Looking at Fossils Flashcards
The remains or physical evidence of an organism preserved by geologic processes
Fossil
Hardened tree sap that traps insects
Amber
A process in which minerals replace an organism’s tissue
Petrifaction
A process in which the pore space in an organism’s hard tissue, for example bone or wood, is filled up with mineral
Perminerlaization
Another form of petrifaction
Replacement
A fossilized mark that is formed in soft sediment by the movement of an animal
Trace fossil
A third type of trace fossil, is preserved in animal dung
Coprolite
A mark or cavity made in a sedimentary surface by a shell or other body
Mold
A type of fossil that forms when sediments fill the cavity left by a decomposed organism
Cast
A fossil that is found in the rock layers of only one geologic age and that is used to establish the age of the rock layers
Index fossils
A fossil of a genus of ammonites; marine mollusk similar to a modern squid; index fossil
Tropites
A fossil of a genus of trilobites; another example of an index fossil
Phacops
Sticky tar
Asphalut
Index fossil
Ammonites
