Lutetian limestone

Lutetian limestone (in French, calcaire lutécien, and formerly calcaire grossier) — also known as “Paris stone” — is a variety of limestone particular to the Eocene-aged deposits in the Paris Basin of France, most notably underlying the city of Paris. It has been a source of wealth as an economic and versatile building material since ancient Roman times (see Mines of Paris) and has contributed markedly to the unique visual appeal of the “City of Light”. It has been hailed as “the warm, elusive, cream-grey stone of the French capital”. In addition to Paris, the Lutetian limestone also extends north and eastwards through France, and has also been mined in areas such as Rheims, Laon and Soissons.

Its formation dates to the Eocene epoch's Lutetian age, between 48.07 and 41.03 Ma. The name "Lutetian" derives from Lutetia (French, Lutèce) which was the name of Paris in ancient times. The Lutetian age was named after the limestone of this region.

The limestone consists of two different ages and depositional environments: a marine limestone deposited during the middle Lutetian (the iconic calcaire grossier) and a slightly younger freshwater limestone (alongside marl) deposited on top of the marine limestones during the later Lutetian, when the seas had receded.