Lou NAO GEOLOGY 
FANUARY—FEBRUARY 1900 
SUGGESTIONS REGARDING THE CLASSIFICATION 
OF THE IGNEOUS ROCKS 
IT may well be doubted if there is any science which presents 
greater difficulties to the teacher than that of systematic petrol- 
o; y—the classification of rocks. Even the name itself is seldom 
us ,and appeals to the petrologist as almost a misnomer, because 
th science is so lacking in system, or, shall we say, over- 
burdened by ‘“‘systems.”” The German petrologists, under the 
leadership of Rosenbusch and Zirkel, and the French with 
Michel-Lévy at their head, are committed to the partial use of 
) 
‘“‘systems’’ which are regarded as obsolete by their colleagues 
in other lands. The English and American schools of petrology 
have each their ‘‘systems” which differ from the German 
‘“systems’’ and more or less from each other. Yet as all are 
using essentially the same language of terms, the confusion which 
has arisen is so great that it is now necessary in employing a 
rock aame to state at length what meaning the word is intended 
to convey. 
Such a state of affairs is explainable on two grounds: first, 
the hesitancy felt in departing from the views held by the 
fathers of the science, and, second, the inherent difficulties 
which lie in the science itself, due to the complex nature of 
rocks. 
Vol. VIII, No. 1. I 
