338 - WHITMAN CROSS 
termed classifications of rocks were published: before the nine- 
teenth century began. Thus in 1787 appeared Karl Haidinger’s 
Systematische Einthetlung der Gebirgsarten (Vienna) and A. G. 
Werner’s Kurze Classification und Beschreibung der verschiedenen 
Gebirgsarten (Dresden). The former essay, though awarded a 
prize by the St. Petersburg Academy of Sciences, appears based 
upon a superficial knowledge of rock masses when compared 
with the Wernerian arrangement. In these and other contem- 
poraneous systems it is plain that the geological formation was 
not distinguished from the rock, as we now use these terms, 
and hence there was no true petrographical scheme at this time. 
Werner's classification of rock formations.—Werner devoted 
much careful study to the mineral composition and general char- 
acteristics of rocks, and often described them in appropriate and 
precise terms. He distinguished between szmple and compound 
rocks, and recognized that in many cases certain minerals were 
to be considered as accessory as compared with other essential 
constituents. Perhaps more than any other geologist he laid 
the foundations of descriptive petrography, but his systematic 
arrangement was so predominantly devoted to expressing a sup- 
posed order of superposition of rocks in the earth that it was 
rather a crude stratigraphic scheme than a classification of rocks 
which he presented. This will be clear from the outline given 
below. 
Werner applied the term ‘‘formation” to masses of a certain 
character originating under certain conditions and perhaps recur- 
ring at various times in the history of the earth. Formations 
were grouped according to the great periods of their origin. He 
distinguished: 
1. Primitive formations (Das Urgebirge): Under this head 
are found granite, gneiss, mica schist, clay slate, limestone, 
quartzite, porphyry, pitchstone, serpentine, and many other 
formations. 
2. Transition formations (Das Uebergangsgebirge): Here were 
placed clay slate, graywacke, greenstone, gypsum, etc. The 
oldest fossils were supposed to occur in these rocks. 
