SVSLEMATIC PETPROGRKAPHY 339 
3. Stratified formations (Das Hlotzgebirge): In this division 
are found sandstone, stone coal, marl, rock salt, various lime- 
stones, chalk, basalt, amygdaloid, and other formations. 
4. Alluvial formations (Das aufgeschwemmte Gebirge): Here 
occur sand, clay, gravel, etc. 
5. Volcanic rocks (Vulkanische Gesteine): This includes only 
lavas and ejectamenta of volcanoes, with several pseudovolcanic 
substances." 
The great majority of igneous and metamorphic rocks, as we 
now term them, were believed by Werner to be of aqueous ori- 
gin, and were treated as such. In Werner’s mineralogical system 
many rocks also found a place, as appears in von Kobell’s state- 
ment of his system as it was in 1798. For example, under the 
clay family (Zhongeschlecht) are included, among others, pitch- 
stone, clay slate, basalt, wacke, clinkstone, lava, and pumice.’ 
DEVELOPMENT OF SYSTEMS IN THE NINETEENTH CENTURY. 
At the beginning of the century, then, the attempts at the 
systematic classification of rocks were progressing on two very 
ditferent= lines” On) ithe one’ hand the mineralogist, treating: 
rocks as an appendage to mineralogy, was arranging them pri- 
marily by their mineral constitution, as far as he could determine 
it, and was for the most part uninfluenced by considerations of 
geologic origin or occurrence. His system was -founded upon 
the most obvious characteristics of the objects in question. 
On the other hand, the geologist was hampered by his 
efforts to arrange in one system geological terranes (forma- 
tions) and rocks proper. He could not logically apply any 
criterion throughout the system, and was most inclined to use 
geological occurrence and theoretical considerations of origin. 
The geologist’s early classifications of rocks were naturally 
more complicated and less logically and consistently carried out 
than the schemes of mineralogists, and were correspondingly 
This general statement of Werner’s elementary system I have taken principally 
from A. VON ZITTEL’s Geschichte der Geologie und Paleontologie, 1899, p. 89. 
2F. VON KOBELL, Geschichte der Mineralogie, 1864, p. 165. 
