A fossil replica created when a mold, often formed by the dissolution of an original organism buried in sediment, becomes filled with secondary material such as minerals or sediment, resulting in a positive impression of the original organism. An example is the formation of a seashell impression in mud which subsequently fills with sand that hardens into sandstone, creating a stone replica of the shell.
This particular form of fossilization offers significant insights into the external morphology of ancient organisms, even in cases where the original organic material has completely decayed. It provides valuable data for paleontological reconstruction, enabling scientists to understand the size, shape, and surface features of extinct life forms. The preservation of external details contributes significantly to our understanding of evolutionary relationships and past ecosystems.
