The animal pictured in our logo is Cooperoceras texanum, an extinct cephalopod mollusk. Cephalopods include the living octopuses, squids, and cuttlefish. Cooperoceras, like many extinct cephalopods, retained an external shell. In this regard, it resembles its closest living relative, the chambered nautilus. For information on the tree of cephalopod evolution, check out the cephalopod pages of the Tree of Life web site.
Shelled cephalopods were very common and diverse up until roughly 70 million years ago. For this reason, they have an extensive fossil record. In addition, cephalopod lineages evolved very rapidly. This means that if you can identify a cephalopod fossil, you can also closely constrain the age of the rock in which it it is found. For this reason, cephalopod fossils are of great interest to geologists, and are good examples of the subtle interactions of Earth and Life sciences.