INTRODUCTION. 85 



in his study of the sedimentary series on the northern slopes 

 of theThuringian Forest. His comprehensive work, Geognostic 

 Contribution to the Knowledge of the Copper Slate Series, with 

 special reference to a part of Mansfeld and Thuringia (Freiberg, 

 1807-15, in 4 vols., and with coloured geognostic map), still 

 ranks as one of the most accurate local monographs on the 

 geology of North Germany. It depicts the different deposits 

 according to their mineralogical character, their stratigraphical 

 succession, their cartographical distribution, and the occurrences 

 of fossils and minerals, in a manner so exhaustive, that later 

 authors have been able to add little to his results. 



Freiesleben included under the term copper-slate or ore- 

 bearing series the strata from the "Red Underlyer" to the 

 " Muschelkalk" inclusive; in other words, all the sub-divisions 

 now placed in the Dyassic and Triassic geological systems 

 were treated by him as belonging to one great formation. 



While the Thuringian Forest and the Harz mountains 

 received by far the largest share of attention from the early 

 geologists, certain other parts of North Germany also found 

 their way into geological literature. The neighbourhood of 

 Hildesheim was made the subject of research papers by 

 J. H. S. Langer in 1789, and again by J. A. Cramer in 1792. 

 A paper entitled " Physical and Mineralogical Observations 

 on the Mountains of Silesia," by A. Gerhard, appeared in the 

 Reports of the Royal Academy of Berlin in 1771 ; and in 1795 

 the mineralogist, D. L. G. Karsten, published a geognostic 

 account of a journey in Silesia. Still more widely read were 

 Leopold von Buch's writings on Silesian districts. His Attempt 

 at a Geognostic Description of Silesia, which he dedicated to 

 Professor Werner, is accompanied by a coloured general map. 

 This paper, like Von Buch's earlier paper on the district of 

 Landeck, is more concerned with petrographical than with 

 geological details, yet it affords a good general survey of the 

 geological structure of a territory previously little investi- 

 gated. 



An individual charm is lent to this and to all the subsequent 

 works of Leopold von Buch by Kis skilful delineation of the 

 relations between the geological structure and the superficial 

 aspects of a country. A landscape appealed to his artistic 

 sense as well as to his scientific interest, and his mastery of 

 language enabled him to transfer his impressions picturesquely 

 in- writing. Mineralogical descriptions were fully given; but 



