Where Are The Most Common Fossils Found? Sedimentary Rocks

Trilobite fossil

Animals, plants, and micro-organisms that died hundreds of thousands of years ago are preserved through time in the form of fossils. Fossils are located across the globe in regions with varying climates. If you are searching for fossils, consider the type of material that contains most fossils and the areas with the highest concentration of that material.

Image by Kevin Walsh from Flickr

Types of Materials That Contain Fossils

Where are the most common fossils found? It is an important question to consider before exploring for fossils. There are three main types of rocks that could contain fossils. These include igneous rocks, sedimentary rocks, and metamorphic rocks. The vast majority of fossils are found in sedimentary rocks. This type of rock develops over time from sediments that are deposited by wind and rain. It is the most common type of rock on Earth.

There are three types of sedimentary rocks. These include clastic, chemical and organic. The majority of fossils are found in clastic sedimentary rocks such as shale and sandstone. This type of rock is formed from mechanical weathering debris. Fossils are also found in limestone.

Besides sedimentary rocks, fossils are also preserved in amber, which is formed from tree sap or resin. Usually, insects are the unfortunate organisms that get trapped and preserved in amber. Tar pits are another preservation medium for some animals.

Areas with Exposed Sedimentary Rocks

Since most fossils are found in sedimentary rocks, the best place to look for fossils is areas with exposed sedimentary rocks. Most quarries, strip mines, gravel pits, and road-cuts feature outcrops and exposed sedimentary rocks. These sites may be privately owned, so check with the companies before exploring and collecting fossils. Other areas that contain exposed sedimentary rocks include creek beds, river beds, lake banks, and ocean banks.

Use Geologic Maps

To search for land that contains sedimentary rocks, it is best to use a geologic map. The geologic map displays areas with sedimentary rocks by color. Usually, sedimentary rocks are indicated by shades of brown, yellow, or green. Geologic maps are also helpful for identifying rocks from a specific era. For example, if you are searching for dinosaur fossils, it is best to look in areas that contain sedimentary rocks from the Mesozoic era. Furthermore, geologic maps are great for locating outcrops, which are areas where rocks are exposed at the surface.

Famous Sites Containing Fossils

  • Bear Gulch Limestone – Located in central Montana, southeast of Lewistown, this site is a multi-layered limestone outcrop that contains a variety of fossils. Over 130 species of fish have been discovered in this area, and numerous arthropods, sponges, and starfish are fossilized in Bear Gulch.
  • Burgess Shale – Located near Fields, British Columbia, this is a major site for invertebrate fossils. Numerous species of mollusks, crustaceans, trilobites, and worms are buried here.
  • Ediacara Hills – Located north of Adelaide, Australia, this hillside contains soft-bodied organisms from the late Precambrian era. The fossils here resemble jellyfish, worms, and arthropods.
  • Beecher's Trilobite Bed – Located near Rome, New York, this quarry contains a vast collection of well-preserved trilobites.

Before embarking on a fossil hunting expedition, ask yourself where are the most common fossils found? Plan your dig at sites with exposed sedimentary rocks. Quarries and river beds are great places to search. Consult geologic maps to pinpoint areas that are most likely to yield fossils.


1. https://paleo.cc/kpaleo/fossfind.htm

2. https://geology.com/rocks/sedimentary-rocks.shtml

3. https://www.pbs.org/wgbh/nova/trex/dig/geologicmap.html

4. https://geology.about.com/od/lagerstatten/WorldClass_Fossil_Sites.htm