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| Description: Correlation of Rock Layers Matching rocks of similar age in different regions Often relies upon fossils Fossils: Evidence of Past Life Remains or traces of prehistoric life Types of fossils Petrified – cavities and pores are filled with precipitated mineral matter Formed by replacement – cell material is removed and replaced with mineral matter Mold – shell or other structure is buried and then dissolved by underground water Cast – hollow space of a mold is filled with mineral matter Types of fossils Carbonization – organic matter becomes a thin residue of carbon Impression – replica of the fossil’s surface preserved in fine-grained sediment Preservation in amber – hardened resin of ancient trees surrounds an organism Types of fossils Indirect evidence includes Tracks Burrows Coprolites – fossil dung and stomach contents Gastroliths – stomach stones used to grind food by some extinct reptiles Conditions favoring preservation Rapid burial Possession of hard parts Fossils and correlation Principle of Fossil Succession Fossils succeed one another in a definite and determinable order Proposed by William Smith – late 1700s and early 1800s Picture Stats: Views: 256 Filesize: 1.25MB Height: 921 Width: 853 Source: https://biology-forums.com/index.php?action=gallery;sa=view;id=39577 |