414 
CROSS. 
of petrography. A large part of the descriptions to be found 
are based upon the statements and follow the classification 
presented by Professor Rosenbusch in his “ Physiographie 
der massigen Gesteine.” Messrs. Fouque and Michel-Levy 
are followed even more closely by French writers, and current 
English literature of this subject has in a certain measure 
an individual tone. 
The classification of spherulites presented by Professor 
Rosenbusch* is a modification of that proposed by Vogelsang. 
It establishes six divisions, namely: 1st, Cumulites; 2nd, 
Globospherulites; 3rd, Granospherulites; 4th, “ Sphaerokrys- 
talle;” 5th,Pseudospherulites; 6th, Felsospherulites, or spher¬ 
ulites proper. Cumulites and globospherulites are almost 
wholly of theoretical importance. They consist of primitive 
globulites—unindividualized matter—a radial arrangement 
of these particles distinguishing the second group from the 
first. Granospherulites are composed of distinct mineral 
grains without any regular arrangement. A spherulite con¬ 
sisting of but a single mineral and exhibiting a radiate 
structure is a “ Sphserokrystall.” A radiate aggregate of 
chlorite leaves is mentioned by Rosenbusch as* an illustra¬ 
tion of this group of spherulites. .It is clear that these first 
four classes of spherulites include but comparatively few of 
the bodies found in rocks, and only those of minute size. 
For the more abundant, more complex, and as prominent 
rock constituents, more important, spherulites, but two groups 
are provided by Rosenbusch, the pseudospherulites and the 
felsospherulites, between which he draws what must be char¬ 
acterized as a very remarkable distinction. If a complex 
spherulite of radiate structure consists only of identifiable 
minerals it is a psewdo-spherulite, while if there is an unde¬ 
termined element, in addition to the known substances, we 
have before us a true spherulite. This distinction illustrates 
another phase of the idea that spherulites proper cannot 
consist of definite minerals ; for while the presence of crys¬ 
tallites is not essential to the felsospherulites, Rosenbusch 
* Rosenbusch (H.). Mik. Phys. der mass. Gesteine. 2d ed. 8°. Stutt¬ 
gart, 1887, pp. 392-3. 
