- Society for Sedimentary Geology
The Tlayúa Quarry, sometimes referred to as the Mexican Solnhofen, is one of the most important fossil localities in Mexico, with fishes making up 70%–80% of the macrofossils. White cryptocrystalline hydroxyapatite patches within many specimens reveal details of muscles, gills, digestive tract, and stomach contents under the scanning electronic microscope. This is the first record of soft-tissue preservation of this kind in Mesozoic fishes from North America. The association of terrestrial, freshwater, and marine organisms, including shallow marine foraminifera, together with abundant ooids and isotopic evidence of fresh water higher in the sequence, favor a shallow, restricted-marine paleoenvironment.