Friday, August 24, 2007
Thursday, August 23, 2007
Friday, August 10, 2007
Friday, August 3, 2007
The present-day configuration of the Chesapeake Bay emerged, with the deposits of the Calvert Cliffs that were once sea bottom now standing 100 ft. above the water line. Fossil remains of animals from that ancient sea floor are now exposed as wind and water erode the cliffs, and represent the most extensive assemblage of this period in the Eastern United States.
The teeth of extinct sharks most commonly found here belong to the following species: Galeocerdo contortus, and G. triqueter (Tiger Sharks), Hemipristis serra (Requiem Shark), Oxyrhina desorii (Mackerel Shark), Sphyrma prisca (Hammer-head Shark), and the Sand Shark, Odontaspis elegans. Teeth of the spectacular giant White Shark, Carcharondon megalodon, are found here too, but are rare.
There are several reasons for this abundance. First, sharks have an unlimited supply of teeth. No cavities, permanently missing teeth, or tooth aches for them! Shark teeth are not set firmly in the jaws, but in the gums, where they occur in layered rows. If a tooth is lost, it is gone but briefly, for another from the reserve layer moves forward to take its place. Also, recent studies indicate that the young of one common modern shark replace their upper teeth every 7.2 days, and the lower ones every 8.2 days! It is possible that this may have held true in fossil sharks.
Check out our Chesapeake bay sharks teeth fossil jewelry and get a little history of your own.