1. Where Did It Go? Footprints made by prehistoric animals might be one of the most intriguing types of fossils. Especially when they are in a series made by the same animal, called “trackways”. Footprint and trackway fossils show the path of the animal and capture a moment in time of the daily life of these long past animals. Trackways can also include impressions made by other parts of the animals such as the snout or tail.
2. Special FX. Buried under layers of sediment, a plant or animal will eventually decay. The impression left of it’s body is called a mold fossil. Sometimes other sediment will fill in the space and this is what’s known as a cast fossil. It’s like natural history’s own special effects and sculpture warehouse.
3. Rock Solid. Also known as petrifaction, the pores of the hard parts of the organism are filled with minerals. Either by the process of permineralization or replacement. These two process both leave similar replicas of the organism, even down to the microscopic level. Petrified wood is common, but other organisms including vertebrates and even bacteria have succumbed to this type of fossilization.
4. The Whole Shebang. These fossils are probably the most stunning. Whole organisms, including soft tissue, are preserved in ice, tar and even tree sap. Prehistoric insects trapped in tree sap later harden to make amber. Wooly Mammoths encased in ice and also the many mammals and plants preserved in the La Brea Tar Pits in Los Angeles, CA are some of the most well known. Last year a hundreds of Ice-Age organisms were discovered in a sink hole in Wyoming. The cold and dark conditions allowed for their preservation.
5. Look What I Almost Stepped In. Coprolites, pleasant name aside, are fossilized poop. Yep, the unpleasant business of an animal’s, er, business can be well preserved. Their location reveals where the animal lived. Fossilized feces can also reveal information about the diet of the animal that pooped it out. Gross? Most likely. Captivating? You bet.