The Geology of Delaware

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The Geology of Delaware » Fossils » Fossil Identification Sheet

Fossil Identification Sheet

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Belemnite

In Delaware, the best place to look for Belemnitella americana is in the dredge spoil piles on the north side of the Chesapeake and Delaware Canal, just west of St. Georges and also just east of the north side of the Reedy Point Bridge. On July 2, 1996, belemnite was named as the official fossil of Delaware. More information can be found at Delaware's State Fossil.

Bivalve Steinkerns and Molds

A steinkern is an internal mold, or a type of fossil formed when a shell fills with mud that later hardens. The external molds of shells are also commonly fossilized. These molds were produced by shells of bivalves, the group of molluscs with two hinged shells such as clams, oysters, and scallops in Delaware's ancient seas. These bivalve steinkerns and molds are from the late part of the Cretaceous Period, approximately 65 to 85 million years old. These fossils were found along the Chesapeake and Delaware Canal.

Fossil Scallop

Along the western shore of the Chesapeake Bay in southern Maryland is a famous fossil collecting area known as the Calvert Cliffs. Among the many shells are beautiful fossil scallops, including forms like this called Pecten or Chesapecten. These fossils are from the Miocene epoch, between 5 and 25 million years old.

Gryphaea

Gryphaea is an oyster that lived in Delaware's shallow seas during the age of the dinosaurs. This fossil can be found along the Chesapeake and Delaware Canal, within the Mount Laurel Formation and the Marshalltown Formation, which were deposited between 65 and 85 million years ago during the late part of the Cretaceous Period.

Marine Mammal Bone

Along the western shore of the Chesapeake Bay in southern Maryland is a famous fossil collecting area known as the Calvert Cliffs. Among the shells are common bones and bone fragments which are the remains of ancient marine mammals (probably dolphins, whales and seals). Note the spongy appearance of the bone. These fossils are from the Miocene epoch, between 5 and 25 million years old.

Petrified Wood

Petrified wood may be found in pits and stream banks in northern Kent County and southern New Castle County, Delaware. This petrified wood occurs near where porous, sandy layers lie on layers that contain abundant fossil diatoms. Diatoms are microscopic shells made of silica, the same compound as opals. The silica is dissolved by water passing through the sand. When this water flows to and soaks the buried wood, it can recrystallize and fill the pores in the wood. The central Delaware petrified wood is from either the Miocene epoch (5 to 25 million years ago) or the Pleistocene epoch (10,000 years to 2 million years ago).

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