Complex sentence: Ours-Pierre-Armand Petit-Dufrénoy (September 5,1792-March 20,1857), French geologist and mineralogist, was born at Sevrati, in the "départment" of Seine-et-Oise.
Split into simpler sentences: Ours-Pierre-Armand Petit-Dufrénoy (September 5,1792-March 20,1857) was a French geologist and mineralogist. He was born at Sevran, in the "département" of Seine-et-Oise.