DECHEN, HEINRICH VON (180o-1889), German geolo gist, was born in Berlin on March 25, 1800, and was educated in the university in that city. He was in the service of the mining department of the Prussian State for 44 years in all, being its director from 1841 to 1864. He paid special attention to the coal formation of Westphalia and northern Europe generally and wrote some important works on the mineralogy of the Rhineland, but his main work was a geological map of Rhenish Prussia and Westphalia in 35 sheets on the scale of 1:8o,000, issued with two volumes of explanatory text (18 5 5-8 2) . He published also a small geological map of Germany (1869) . He died at Bonn on Feb. 15, 1889.