![](http://www.alamy.com/thumbs/6/1FB98C9A-8171-4ACF-BC2E-D568E5B7E4F3/2ACJHE2.jpg)
Limestone concretion on a shale slope. A concretion is a sedimentary rock in which a different mineral has filled it's porous structure like a cement.
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Photo credit: © DIRK WIERSMA/SCIENCE PHOTO LIBRARY / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: cliff, concreted, concretion, earth, geographical, geography, geological, geology, limestone, mineralogy, physical, rock, rocks, rocky, science, sedimentary, shale, slope