Salt marshes like the one shown in (A) are often found in lagoons. This is where muddy sediment, rich in organic material, collects. This muddy sediment may eventually form a rock like the shale shown in (B). Sometimes there are little layers in the shale called laminations that formed when the sediment settled down to the bottom of the lagoon. Other times, plant roots disrupt the laminations and they are impossible to see.
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(A) Bruce Molnia, Terra Photographics courtesy of Earth Science World Imagebank and (B) courtesy of State of New York.
Last modified January 6, 2004 by Lisa Gardiner.
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