Silicone casting

A whole collection of limestone chunks was recovered from the mine in Freital near Dresden, Germany, in the 19th century. In addition to numerous amphibians from the Permian period, they contain the only series of baby pelycosaurs found in the world. The disadvantage in terms of preparation is that the matrix rock is very hard, whereas the bone is soft and brittle. Either it crumbled out of the split slabs immediately after being found, or the bone substance was deliberately removed. This happened a long time ago and cannot be reversed. The incredibly detailed impressions in the rock have remained and reveal the finest vascular openings or needle-like palatal denticles. Due to the fact that the skeletons are often disordered, molds made with ultra-fine silicone served as the basis for the graphic analysis. In one case you can see the lower jaw spread open, and in one of the largest peels you can even see half of the face with the upper and lower jaws matching.

get article via researchgate: Spindler, F. (2016): Morphological description and taxonomic status of Palaeohatteria and Pantelosaurus (Synapsida: Sphenacodontia). Freiberger Forschungshefte C, 550(23): 1-57.