how to find fossils
How to find fossils
Fossils are found
in sedimentary rocks most of the time. Sometimes fossils can be found
volcanic ash or even preserved under a lava flow, but this is very
NOTE: Sedimentary rocks do not always have fossils in them.
Layers are a characteristic of sedimentary rocks. The bottom layers are naturally the oldest.
Some types of rocks found in the layers:
mainly calcium carbonate, common in warm, shallow seas, often has
Shale is a fine grained rock formed from silt and clays. It preserves fossils well.
Sandstone is widespread in desert deposits and on shallow water sediments.
Ripple marks and Mud cracks are characteristics of many sedimentary rocks formed in shallow waters. Ripple marks are common in shale. Mud cracks are form when mud drys quickly. These imply the presence of sunlight, water and moderate temperature conditions related to the possibilities of life.
WHERE TO LOOK
CREEK BEDS AND BANKS
1.Start at the
bottom of the creek
2.Look for fragments of bone
3.Follow them up the creek looking for larger, more angular bits as you go
4.When the bits of bone stop. Look up on the banks for the fossils
5.Find the larger piece of bone and excavate it
LOOKING AT INDEX FOSSILS
An index fossil is a fossil that is useful in working out the age of a bed of rock. You need several index fossils in combination to got a good date.
A good index fossil needs:
- To be easy to identify
- Exists over a short geological time range
- Has worldwide distribution
A simple example shown below
A more complex example shown below