Petoskey Stones were formed by the fossilization of ancient coral, Hexagonaria. The coral lived in shallow waters. Petoskey Stones are found on many beaches of Lake Michigan and Lake Huron. Petoskey stones, only found in Michigan.
Ammonite,Sphenodiscus lenticularis, from the Fox Hills Formation, South Dakota.Both sides display intricate suture patterns and an iridescent nacreous layer. This laterally flattened Ammonite is thought to be a fast swimmer.
A Petoskey stone .is a rock and a fossil, often pebble-shaped, that is composed of a fossilized coral that lived 350 million years ago. The rocks rounded in the surf along the shores of Lake Michigan near Petoskey, Michigan.
frontal-cortex: Scanning electron microscope picture of a nerve ending that has been broken open to reveal the synaptic vesicles beneath the cell membrane. Image by Tina Carvalho. The Cell: An Image Library