COPROLITE OR PSEUDOCOPROLITE - Madagascar

Coprolites are fossilised faeces which provide valuable evidence for a prehistoric animal's diet. However, the coprolites found at some sites, notably in Washington State USA, Madagascar and elsewhere, have proved controversial.

At some sites the coprolites do not contain any fossilised food particles, they lack calcium phosphate, and consist entirely of the mineral siderite (iron carbonate). Some geologists have interpreted them as intestinal casts, and others have suggested that they may have no biological origin. But many still believe they are coprolites, and judging from how realistic they sometimes are, it is hard to disagree.

If they’re not coprolites they must, as one leading geologist has said, "have been produced by an anomalous process without a modern analogue. We are fundamentally missing something”.

  
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