CONNOR: Good thinking! I read a bit about limestone on the bus journey. Limestone is a sedimentary rock created by layers of skeletons and shells of sea creatures found in ancient, warm ...

Limestone, made from calcium carbonate, takes millions of years to form. These sedimentary rocks are born from the decay and fossilization of marine organisms — think coral and clams.

Unusually small burrows, i.e., tiny tubes that run through the rock in a parallel arrangement from top to bottom, were discovered in marble and limestone of these desert regions. In the desert ...

Rainwater also mixes with chemicals as it falls from the sky, forming an acidic concoction that dissolves rock. For example, acid rain dissolves limestone to form karst, a type of terrain filled ...