ANNIVERSARY ADDRESS OP THE PRESIDENT. 4 1 



Geological Map of Saxony was entertained as early as 1780 ; and 

 during Werner's lifetime a conimeneement was made by dividing 

 the country into 90 districts, which were allotted for examination 

 among the different mining-officials and other competent observers. 

 In 1830 the revision and reduction of these preliminary observations 

 was confided to C. F. J^aumann, then Professor of Geology at 

 Freiberg, with a view to their publication upon the large military 

 map of Saxony on the scale of jyoWoo (rather more than half an 

 inch to a mile) ; and in a short time Cotta became associated with 

 him in the work. Owing to the great cost, however, only the 

 more interesting portions, containing the kingdom of Saxony proper, 

 were published, between 1836 and 1844. These form twelve sheets 

 in a connected block, the numeration^ however, being that of the larger 

 military map. The last of these was published in 1843 ; but some 

 of the sheets have been revised and issued at later dates. In 

 addition to a short pamphlet, a detailed description was drawn up 

 for each sheet ; but only five of these appear to have been published : 

 the first two were written by Kaumann, the third by Naumann and 

 Cotta, and the remainder by Cotta alone. 



Subsequently the Survey was extended to the Thuringian 

 country, the map (forming four sheets on the same scale) being pub- 

 lished by Cotta alone in 1845-1847. These maps may be considered 

 as the first exact and systematic national surveys made on the con- 

 tinent of Europe ; and they are remarkable for the large amount of 

 exact detail given, on what is now regarded as a comparatively 

 small scale — seventy different colours and signs being employed in 

 their construction. The improvement of geological cartography 

 was to the last a favourite subject with this author; and by one of 

 his latest official acts, urging upon the Government the necessity 

 of larger and more detailed maps, he was a powerful instrument in 

 the initiation of the new survey on the scale of ■2^^jf^, uniform 

 with that of Prussia, which is now being carried out under the 

 direction of Dr. Credner. 



In 1842, on the translation of ISTaumann to the University of 

 Leipzig, Cotta succeeded him as Professor of Geology at Preiberg, 

 adding to his geological lectures in the following year a course on 

 Palaeontology, and in 1851 another on the special phenomena of 

 mineral deposits (Erzlagerstattenlehre), which three subjects he 

 taught continuously until his retirement in 1874. Prom his frank 

 and genial manner he was always a great favourite with his 

 students, his classes being well attended : but he was even more 

 successful as a demonstrator in the field ; and his excursions were 

 always extremely popular, even with those students who were not 

 immediately connected with his classes. 



In addition to works descriptive of geological maps, Cotta was a very 

 industrious writer of text-books, biographical memoirs, and popular 

 works on geology, the total number of his memoirs and other publica- 

 tions amounting to about eighty. Among the first the more important 

 are his ' Gesteinslehre ' and ' Lehre von den Erzlagerstatten ' — the 

 former a treatise on rocks, which appeared in 1855, a second edition 



