60 – 500 million years old, ammonites are an extinct form of mollusk related to the octopus and chambered nautilus. Like the nautilus, it had a hard shell with a distinctive spiral pattern. Ammonites range in size from 1 mm to over 2 feet, and vary in the type of mineral replacement during fossilization. The name comes from its resemblance to a ram’s horn: in Egyptian mythology, the God Ammon looked like a man with horns like a ram. Ammonites are found in Canada, Europe, Madagascar, Peru, and Morocco.
520- 250 million years old, trilobites are an extinct marine arthropod – a family including present-day crustaceans and spiders. There are thousands of known species of trilobites ranging in size from 1 mm to over 2 feet. Trilobite bodies are characterized by three lobes (tri-lobe): the cephalon (head), thorax (body), and pygidium (tail). They were among the first animals to develop complex, compound eyes, with lenses made of calcite. Trilobite fossils are found on every continent; locations include Utah, New York, and Morocco.
C. megaladon (from”big tooth” in Greek) was the biggest shark that ever lived and the largest marine predator in the history of the planet. Now extinct, it roamed the seas 26 to 2.6 million years ago. This distant cousin of the mako shark is thought to have been the size of a railroad box car (approx. 60 feet long) and weighed 50 – 75 tons. Megaladon had the most powerful bite of any creature that ever lived (estimated at 10-18 tons of force), which it used to hunt whales, dolphins, fish, squid and sea turtles. Adult Megalodon teeth were typically in the 4-5 inch range, with teeth over 6 inches being rare and representing super-sized individuals. Fine specimens are found in the Carolinas and Florida.
Orthoceras (“straight horn”) is an extinct squid-like mollusk from the Ordovician period, about 450 million years ago. The creature lived in the last open segment on the wide end of the shell, and ranged from 1 cm to 6 ft long. As the body outgrew the segment, a dividing wall, called the septa, grew to separate the old home segment from the new. A small tube, the siphuncle, runs down the center of the shell and was used for propulsion and buoyancy. These fossils are found in the Atlas Mountains of the Sahara Desert in Morocco.