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.

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 ...

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. The paper is ...

In some locations there are land plants and reptile tracks. This layer of rock, known as the Redwall Limestone, forms a sheer cliff 500 ft high or more in most areas. The limestone gets its color ...

Mysterious micro-burrows in desert marble and limestone were probably made by microbes that lived millions of years ago. Exactly what kind of microbes bored into the rock remains unknown, as does ...

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 ...