Jean Baptiste Julien d'Omalius d'Halloy

Jean Baptiste Julien d'Omalius d'Halloy was a Belgian statesman and geologist. He was the first to define the Cretaceous as a distinct geological period, in 1822. He produced the first geological map of France, the Benelux, the Rhineland and Switzerland, completed in 1813 and published in 1822. Halloysite, a clay mineral, was named in his honour. He also wrote on races.