182 The American Geologist. September, vest 
rock-forming minerals was first recognized in its true significance by 
Ferdinand Zirkel (now of Leipzic), whose further development and 
refinement of the subjecl put an end to the long period of stagnation in 
petrography. At the head of the modern school of petrographers 
stands lirst of all Zirkel. alongside of whom Rosenbusch and Cohen (of 
Heidelberg and Strassburg) are none the less conspicuous, not only on 
account of their penetrating researches, but also for having devised 
most skillful means for bringing the principles of physics and crystal- 
optics to hear on the microscopic analysis of rocks. 
The University of Halle. Prussia, where Germar, Fr. Hoffman, Kefer- 
stein, Girard, and von Fritsch were engaged as geologists, aud Giebel 
and Burmeister as palaeontologists, lays claim to important services in 
the advancement of geology and palaeontology. Breslau, since its call- 
ing, in 1855, of Ferdinand Roemer, the leading authority on Palaeozoic 
formations, to a professor's chair, has been the training school of a Large 
number of Germany's ablest and for the most part still living geolo- 
gists and palaeontologists, such as von Seebach, Schliiter, Hermann 
Credner, Eck, Dames. Tietze, and numerous others. 
The beginning of the present century found a vigorous scientific life 
pulsating in Gottingen University, Hannover. The ideas of Werner, Al- 
exander von Humboldt, and Leopold von Buch fell here on fertile soil. 
While Blumenbach had early grasped the important significance of 
fossils a& means for identifying different strata, his successors. Haus- 
mann, whose investigations were by no means confined to mineralogy 
alone, Sartorius von Waltershausen, and C. von Seebach, rose to a still 
higher degree of influence amongGerman geologists. Sartorius in par- 
ticular, through his monographs on Etna, on the physical geography of 
Iceland, and on the climatic conditions of former periods, enriched sci- 
ence with works of rare learning and of permanent value. 
Among the universities of central and southern Germany, those in 
Heidelberg, Leipzic. Munich and Tubingen are the most important. 
Heidelberg commanded, as early as the third decade of the century, an 
advanced position in the lines of geological and paheontological progress. 
In the person of ('. ( '. von Leonhard, compiler of the Mineralogisches 
Taschenburfi and founder of the Neues Jakrbuc7if<iir Mineralogie, Geologie, 
und Petrefaktenkundi (which, together with the Zeitsehrift der deutecfien 
geologischen GeseUscIiaft, is the most important of all periodicals in geol- 
ogy and palaeontology), the university posessed a lecturer of charming 
eloquence, and a brilliant student of volcanic action and eruptive rocks. 
|i\ his side stood II. (J. liroiin. professor of zoology and palaeontology, a 
man of prodigious scholarship; his Lethaia Geognostiea is one of the bul- 
warks of geological and palaeontological literature, while his Qeschichte 
der Natur and Index Palceontologicus were for many years most indispen- 
sible requisites for every worker in palaeontology. The petrographical 
studies of R. Blum also occupy an enviable position in the geological 
literature of Germany. 
In Leipzic, beginning with 1842, C. F. Naumann lectured in mineral- 
ogy and geology for thirty consecutive years, after having already 
