A 140 million years old spider web has been confirmed. Silk generally does not last that long, but this web was preserved in fossilized amber. The web bears some striking similarities with the ones modern spiders weave. In the same piece of amber, scientists found the oldest known examples of actinobacteria, a bacteria that was important for soil formation.
"Scientists found the rare amber fossil in December, and have now confirmed that it contains remnants of spider silk spun roughly 140 million years ago by an ancestor of modern orb-weaving spiders. After slicing the amber into thin sections and examining each piece under a high-powered microscope, the researchers discovered that the ancient silk threads share several features common to modern spider webs, including droplets of sticky glue used to hold the web together and capture prey.
In addition to ancient spider silk, the amber chunk contains well-preserved soil microbes, including the oldest known examples of actinobacteria, a common type of bacteria that plays a major role in soil formation."