|Single-celled life (fossil stromatolites)|
Single-celled life forms have been the most abundant life forms on earth since life began. Because most of these single-celled beings are soft and decay easily, their fossils are very rare. However, some forms that lived in the sea secreted shells, and fossils of these microscopic shells can be found in Kentucky. People who study these tiny shells and other small fossils are called micropaleontologists. The average fossil hunter will not have the proper equipment to see these abundant fossils.
Colonies of blue-green bacteria (formerly called blue-green algae) living in shallow tropical seas sometimes formed mats on the sea bottom. In certain cases, fine sediment layers (laminae) periodically covered the mats or layers of calcium carbonate that were deposited by the bacteria. Layers of bacterial mats and sediment alternated and formed buildups called stromatolites. Modern stromatolites are found in warm, salty seas in tropical regions around the world. Fossil stromatolites have been found in Kentucky, but are not common. Generally, only the alternating layers are preserved; the individual bacterial cells are not fossilized. Stromatolites were very common in the late stages of the Precambrian Eon and in the early Paleozoic Era before animals that fed upon them evolved. Modern stromatolites exist only in areas that are too salty or too hot for animals that graze upon them.
Some colonial single-celled algae secrete calcareous skeletons that are sometimes preserved as fossils.
Red algae specimen from Kentucky at the Kentucky Paleontological Society webpage.
|Plants(fossil ferns, wood, roots, etc.)|
|Animals(fossil shells, corals, animal bones, etc.)|
|Shellfish, etc. (invertebrates): the most common fossils in Kentucky|
|Backboned animals (vertebrates): includes dinosaurs, fish, mammals, etc.|
|Trace Fossils(fossil tracks and trails)|
Trace fossils are the tracks, borings, nests, trails, bite marks, etc. of ancient organisms. Trace fossils are common and can be very helpful in determining behavoir in extinct animals. The study of traces is called ichnology. Most of the trace fossils in Kentucky were made underwater by invertebrate animals. However, one trace, a reptile trackway from McCreary County was made on land.
Links to other sites
Trace Fossils (trackways, etc.):