File:Coast watch (1979) (20036699554).jpg

Title: Coast watch
Identifier: coastwatch00uncs_7 (find matches)
Year: 1979 (1970s)
Authors: UNC Sea Grant College Program
Subjects: Marine resources; Oceanography; Coastal zone management; Coastal ecology
Publisher: (Raleigh, N. C. : UNC Sea Grant College Program)
Contributing Library: State Library of North Carolina
Digitizing Sponsor: North Carolina Digital Heritage Center

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are Keys to the Past By Natalie Eason Hampton To grasp a fossil in your hand is to hold a hey to the door of the past, en unearthed from the sediments in which they were huried. fossils help scientists reconstruct a picture of what life was like on this planet millions of years ago. Take dinosaur fossils, for instance Information gleaned from these fossils and surrounding sediments has allowed researchers to accurately depict these giants and their habitat. Throw in a little Madison Avenue marketing to capture the fancy of children, and there's hardly a child in America that can't say Tyran- nosaums. All fossils aren't as glamorous or marketable as those of the dinosaur. But all are important to scientists looking for clues about weather patterns, ocean levels, species availability and habitat during ancient geologic periods. When it comes to finding fossils, North Carolina's Coastal Plain offers dozens of sites where professionals and amateurs can dig for fossils millions of years old. You can dig alone or join a fossil expedition sponsored by a club or museum (see story, page 18). Scientifically speaking, fossils are remains, impressions or traces of ani- mals or plants from former geologic ages. Sometimes they are the hard parts of organisms such as shells, bones and teeth that have survived millions of years. Other times, they can be impres- sions or molds left behind by a plant or animal long since decomposed. And yet another kind of fossil, a cast, is a min- eral or sediment replica of the original organism. Fossilization usually begins when the hard parts of an organism become embedded in mud or covered by sand from a river, lake or ocean. These hard parts may remain unchanged for mil- lions of years, despite changes in the
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All photos by Scott D. Taylor. Courtesy of Kieth Sturgeon, North Carolina Maritime Museum surrounding sediments that compress to form limestone or sandstone. However, most fossils are altered through contact with groundwater. Percolating groundwater may cause fossils to lose their original color and luster, become stained with minerals, dissolve or be replaced with minerals such as calcite, pyrite or quartz. Fossil tree trunks and branches may become petrified when their pores are filled with minerals, a process called permineralization. Some fossil wood found in North Carolina is so thoroughly permineralized that it can be cut with a rock saw and polished to show its cellu- lar structure. The ocean has advanced and re- ceded across the Coastal Plain many times during the state's long history. Each time, new layers of soft sands and muds were laid and sometimes eroded. These soft substrates acted as a time recorder, preserving life-forms present during geologic periods known as epochs. Every epoch is chronicled by a geo- logically distinctive layer of sediment. "Each bed (forma- tion) is like a page in a book on the geologic history of the Coastal Plain," says Stan Riggs, a Sea Grant researcher and geologist at East Carolina University. "The entire Coastal Plain (of North Carolina) is made up of marine sediments stacked like a deck of cards." Hundreds of species of fossil plants, seashells, bones and teeth ranging from a few thousand to 80 million years old can be collected from Tar Heel riverbeds, road cuts, beaches, quarries and mines. Sometimes the fossil finds are remains of marine creatures — sharks, whales, Continued COASTWATCH 1 1

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