50 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



versity as Extraordinary Professor of Geology. In 1841 lie 

 returned to Bonn as Director of the Department of Mines (" Ober- 

 bergamtsdirector "), and continued a resident of that city with but 

 trifling exceptions for the remaining forty-eight years of his life. 



In his earlier years v. Dechen made many journeys for the pur- 

 pose of inquiry into the mining systems of other countries, and one 

 of these, made in the company of his friend C. von Oeynhausen to 

 England and Scotland, lasted for more than a year, from September 

 1826 to November 1827. The object of the two travellers was 

 mainly official, to report to their government on the mining, and 

 especially the coal-mining, of England ; but, both being ardent 

 geologists, some of their time was devoted to examining the features 

 of the country. One result of their visit was a paper on Ben Nevis 

 and some other places in Scotland, read to this Society January 19th, 

 1829. After their return v. Dechen and v. Oeynhausen became 

 connected by marriage, the former marrying a sister of the latter's 

 wife, a lady named Gerhard, in 1828. 



A great part of v. Dechen's life was devoted to the official work 

 of mine-inspection, and to him is ascribed a foremost share in the 

 great progress that took place in mining and metallurgical works 

 throughout Rhenish Prussia during the twenty-three years that he 

 was director of the department. But during the whole of that time 

 and for many years afterwards his contributions to geological science 

 were numerous and important. Most of these contributions related 

 to the Rhineland, and his greatest undertaking was the preparation 

 and publication of a geological map of Rhenish Prussia and West- 

 phalia in thirty-live sheets, on a scale of 1 : 80,000 (about 14- inch 

 = 1 mile). This map, together with two volumes of explanatory 

 text, was issued at intervals between 1855 and 1882, and was the 

 first published geological map on a large scale that represented a 

 considerable part of Germany. A map of the area on a smaller 

 scale, ] : 500,000, was issued in 1866; a 'second and improved 

 edition appeared in 1883. Amongst his earlier publications were 

 a translation of De la Beche's ' Geological Manual ' into German, 

 published in 1832, and a general geological map of Germany, France, 

 England, and the neighbouring countries, which appeared in 1838. 

 The interest excited by v. Dechen's Rhenish maps contributed 

 greatly to the establishment of a regular geological survey in Prussia 

 and other States of Germany. 



Among V. Dechen's services to science must be placed in a high 

 rank the effects of his influence on the two scientific Societies of 



