Jules Marcou, a French geologist, born at Salms, in the department of Jura, April 20, 1824. He completed his studies at the col-lege. St. boms in Paris, and published in 1846, in the memoirs of the geological society, his Rerherches geologiques sur le Jura salinois. In the same year he was attached to the min-cralogioal department of the Sorbonne. In 1847, he was employed in classifying the pa-lneontological collection at the museum, for winch institution he made geological inves-tigations m various parts of Europe, and from 1848 to 1850 in the United States and Canada. In 1853 -'4 he explored the Pork v mountains, under the auspires of the American government; and he continued his American explorations in 1860, after having in the interval filled the chair of pakeontological geology at the polytechnic school in Zurich. His principal works are: " Geological Map of the United States " (English, 1853), followed in 1855 by a resume of the same, including Canada; Le terrain car-bonifere dans l'Amerique du Kord; Sur le gisement de Vor en Californie; Lettres sur les rochers du Jura et leur distribution geogra-phique dans les deux hemispheres (1857-160); "Geology of North America" (1858); Drias et trias, ou le nouveau gres rouge en Europe, dans l'Amerique du Nord et dans VInde (1859); Carte geologique de la terre, according to the Jura strata (1862); and Derniers tra-naux sur le drias et le trias en Russie (1870).