A MODE OF FOSSILIZATION IN TURONIAN AND SENONIAN STAGES

        PRESERVATION OF THE SHELL
: the calcareous shell (or the test for a sea urchin) has been preserved less change (or nearly).

 Rhynchostreon suborbiculatum (Oyster)

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A MODE OF FOSSILIZATION IN TURONIAN AND SENONIAN STAGES

        INTERNAL MOULD
: the shell has disappeared but its imprint remains with the sediment which filled it after the death of the animal.

 Granocardium productum

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A MODE OF FOSSILIZATION IN TURONIAN AND SENONIAN STAGES

        EXTERNAL MOULD
: the shell has disappeared but its imprint remains with the sediment which surrounded it.

 Granocardium productum

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A MODE OF FOSSILIZATION IN TURONIAN AND SENONIAN STAGES

        
NATURAL MOULDING : fossilization at two times. At first, formation of an external mould. In a second time, the hollow imprint was filled by a new sediment which, after hardening, reproduces exactly the shape of the living being.

 imprint of fruit ?

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A MODE OF FOSSILIZATION IN TURONIAN AND SENONIAN STAGES

        SILICIFICATION
: after burying of the living being, its molecules were replaced by molecules of silica.

 silicified wood in partially silicified tuffeau