Rock mass discontinuities
" We will confine ourselves here to sedimentary rocks. These are formed from the deposit, for the most part on the seabed, of a variety of materials known as sediments. These sediments are either carried by rivers from the continent (sands, clays), or created chemically by living creatures (molluscs, corals, echinoderms) using substances (carbonate, silica) in solution to form their shells, or tests. When the organism dies, these tests are deposited on the seabed and are gradually cemented together by lime muds..."
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