60 HISTORY OF GEOLOGY AND PALEONTOLOGY. 



1 volcanic rocks in his time Desmarest, Raspe, Arduino, and 

 " Faujas de Saint-Fond. Werner had at first included basalt 

 among the rocks of highest antiquity ; subsequently he re- 

 moved it to the Flotz formation. In 1788, after a visit to 

 the Scheibenberg, a basaltic summit in the Erz mountains, he 

 wrote a special paper on basalt, from which the following 

 passage is extracted : 



" The basalt rock is separated by several beds of sandstone, 

 clay, and greywacke from the basal gneiss. The transition 

 from one stratified bed to the next in upward succession is 

 quite gradual. Even the greywacke merges gradually into the 

 clays below it and the basalt above. Therefore the basaltic, 

 clayey, and sandy rocks all belong to one formation, have 

 all taken origin as moist deposits, precipitated during one 

 particular epoch of submergence in this district. 



"All basalt was formed as an aqueous deposit in a com- 

 paratively recent formation. All basalt originally belonged to 

 one widely extended and very thick layer, which has since 

 been for the most part disturbed, only fragments of the original 

 layer being left." 



Voigt, who had been a scholar of Werner, opposed this so- 

 called "new discovery," and said that the Scheibenberg basalt 

 was of volcanic and not aqueous origin, that it represented 

 an old lava which had flowed over a sandy substratum. A 

 lengthy controversy ensued, in the course of which Werner 

 wrote his paper tracing volcanic activity to the burning of 

 coal in the earth's crust. He argued that during volcanic 

 action basaltic deposits might be converted into lava, if it so 

 happened that the coal-beds were subjacent to the basaltic 

 beds in the crust. The controversy between Neptunists and 

 Volcanists waged for many years in Germany, and much labour 

 and time were lost in the discussion of difficulties which had 

 already been solved in other European countries. 



The New Theory of the Origin of Mineral Veins was 

 Werner's last contribution to science. His theory was that 

 surface-water descends through crust-fissures ; vein-stuff is 

 precipitated from the water, and gradually fills up the fissures. 

 Although this theory is no longer accepted for the majority 

 of ore-deposits, Werner's work proved of the highest value 

 in mineralogical science, since it contained a large store of 

 accurate information about mineral veins, and suggested new 

 methods of determining the relative age of vein-deposits. 



