Here's why:
* Shale is a sedimentary rock formed from the accumulation of fine-grained sediment, primarily clay and silt.
* Coral skeletons are made of calcium carbonate, which can form limestone or dolostone.
* Shale is typically formed in quiet water environments like lakes or oceans, where fine sediment can settle.
* Coral reefs are typically found in warmer, shallow water environments.
While coral skeletons can contribute to the formation of other sedimentary rocks, they don't directly form shale.
