Fossils

450 million year old fossils

Sea Urchin Echinoid

Echinoids (sea urchins and sand dollars) are echinoderms, related to sea stars and crinoids. All echinoderms have external skeletons made of numerous plates of the mineral calcite (a form of calcium carbonate), and a unique water vascular system that drives most of their motion. Echinoids have rounded or flattened shells, called tests, which bear numerous spines. Tiny tube feet, connected to the water vascular system, extend through holes in the test and allow the animals to move on or within the sea floor. All echinoids exhibit the characteristic five-fold symmetry of echinoderms.

450 million year old fossil

Sea Urchin Echinoid

Cephalopods

Cephalopods, such as squid, octopods, nautiloids, ammonoids (see below), and belemnites, are mollusks with tentacles and beak-shaped mouths for catching prey. Some cephalopods such as belemnites and living cuttlefish have internal shells, while others have straight or coiled shells, such as those of ammonoids or nautiloids. Still other cephalopods, such as the octopus, have no shell. The mass extinction at the end of the Cretaceous (famous for eliminating the non-avian dinosaurs) also eliminated belemnites and ammonoids, which had been extremely diverse during the Mesozoic.

Amaltheus fossil

190-185 million years old

Pecten gibbus
Argopecten gibbus

1.8 million years ago

Clade Monocots

Septarian Nodules

Septarian nodules are distinctly sphere-like concretions that are characterized by a series of cracks that widen towards the center and die out towards the sides of the concretion. These radiating cracks are often crossed by a series of concentric cracks giving them a "turtle-back" appearance. Dehydration of the concretion creates the cracks which then are filled with another crystalline cement, such as calcite or silica. They can range in size from 10 to 100 cm in diameter and usually are made up of a large component of iron.