Ammonites are extinct marine mollusks, characterized by their distinctive spiral, chambered shells, commonly found as fossils. These ancient cephalopods, distantly related to modern octopuses and squids, thrived for millions of years before their disappearance around 66 million years ago, coinciding with the extinction of the dinosaurs. Their prevalence makes them a compelling subject for discovery, offering a tangible connection to prehistoric marine life.
Prime Hunting Grounds
Ammonite fossils are found globally, primarily in sedimentary rock formations from marine environments. These rocks include limestone, shale, chalk, and sandstone, formed from sediments on ancient seafloors. Coastal cliffs, such as those along England’s Jurassic Coast, are particularly productive sites where erosion exposes new fossils. Riverbeds and quarries that cut into ancient marine layers can also reveal ammonite-bearing rocks.
These marine sedimentary deposits indicate areas once submerged under vast, ancient seas. Their global distribution across continents highlights their widespread presence in prehistoric oceans. When ammonites died, their shells would sink and become buried in sediment, which then hardened into rock over millions of years, preserving their forms.
Essential Tools and Techniques
Searching for ammonites requires a few basic tools. Sturdy shoes and gloves offer protection, while safety glasses are important when working with rocks. A rock hammer and chisel are fundamental for extracting fossils from rock. For lighter work or cleaning away loose material, a brush can be useful.
Patience is key. Examine exposed rock surfaces, looking for distinctive spiral shapes or patterns that hint at a fossil within. Sometimes, only a small part of the fossil might be visible, indicating a larger specimen embedded in the rock. It is often more effective to look for loose fossils on the surface or within weathered rock rather than attempting to break open solid rock formations indiscriminately.
Identifying and Protecting Your Finds
Recognizing an ammonite fossil involves looking for its characteristic coiled shell. Most ammonites have a planispiral shape, similar to a ram’s horn. However, some species, known as heteromorphs, can exhibit more unusual coiling patterns, including uncoiled, helically coiled, or irregular shapes. The shell’s surface may also show ornamentation like ribs, spines, or tubercles, and internal features like intricate suture lines are visible on some specimens.
Once an ammonite is found, careful handling is important. If loosely embedded, it can often be gently removed. For transport, wrapping the fossil in newspaper or tissue paper provides cushioning and protection. For specimens still partially encased in rock, it is advisable to remove some surrounding rock for protection until further preparation can be done safely at home.
Responsible Collection Practices
Responsible fossil collecting involves adhering to local regulations. Before heading out, research whether fossil collecting is permitted in your chosen location, especially on public lands like national parks, where it is often restricted or forbidden. On private land, always obtain permission from the landowner before collecting. In many areas, common invertebrate fossils, such as ammonites, can be collected in reasonable quantities for personal use, but they cannot be sold.
Safety is a priority when fossil hunting. Be aware of your surroundings, especially near unstable cliffs, and check tide times if collecting along coastlines to avoid being cut off. Inform someone of your location and expected return time, and carry a mobile phone. Minimizing your impact on the environment and leaving the area as you found it ensures these natural treasures remain accessible for future generations.