170 General Notes. 
the great handbook of petrography embraces in its treatment the 
effusive rocks, which are divided into the palæovolcanic and the 
neovoleanic classes. Under the former are included the quartz- 
porphyries, the quartz-free porphyries and keratophyres, the porphy- 
rites, the augite-porphyrites and melaphyres, and the picrite- 
porphyrites. We miss here the elæolite porphyrites, which have 
been relegated to the questionable group of dyke rocks, and the 
quartz-porphyrites, which have been merged into the porphyrite 
family. The melaphyres are now members of the augite-por- 
phyrite family, and the keratophyres have found a home among the 
quartz-free porphyries. There are nowhere as sharp distinctions 
made between rocks of different mineralogical and chemical compo- 
sitions as were found in the first edition of the Mussige Gesteine. 
The classification has become somewhat more complicated than the 
old one, but at the same time it seems more reasonable in the light 
of recent investigations. Among the neovoleanic rocks we find the 
liparites and pantellerites, the trachytes and quartz-free pantellerites, 
the phonolites, the dacites, the andesites, the basalts, the tephrites 
and basanites, the leucite rocks, the nepheline rocks, the melilite 
rocks and the limburgites and augitites. We here also miss a few 
familiar groups. The augite andesites are classed with the ande- 
sites. The tephrites and basanites have been united into one family. 
The entire group of glassy rocks has been eliminated, and the indi- 
vidual members have been included ‘among those families of the 
neovoleanic rocks with which they are genetically connected. The 
discovery of a triclinic potassium sodium feldspar by Férstner’ in 
the sodium-rich liparites of the island Pantelleria has resulted in 
the separation of the old liparite family into two subfamilies— 
the liparites proper, containing sanidine, and the pantellerites 
containing anorthoclase as their principal feldspathic constituents. 
Each family among both the palæovolcanic and the neovoleanic 
effusives is composed of numerous species or varieties, each one of 
in the book be interesting. 
1 Zeits. f. Kryst., 1877, i., p. 547, and 1883, viii., p. 125. 
