838 General Notes. 
to regard variolite as a perlitic tachylite, whose perlitic cracks have 
been filled with secondary minerals——Chelius' divides the dyke 
rocks cutting the eastern and the western areas of crystalline schists 
in Spessart and Odenwald as granite-porphyries and minettes in 
the latter area, and kersantites in the former. The kersantites are 
panidiomorphie aggregates of plagioclase and augite, together with 
hornblende, mica, quartz, apatite and a few rare minerals. The 
panidiomorphic structure passes into the holocrystalline porphyritie 
toward the edges of the dykes. The minettes of the Odenwald 
fall into two groups, the minettes proper, and the vogesites or 
minettes poor in mica. The latter embrace both augitic and horn- 
blendic varieties. The minettes sometimes contain augite and some- 
times biotite as their principal ingredient. The granite porphyries 
s no peculiarity of structure or composition to which attention 
need be called.—The article on the Archzan Geology of Missouri, 
to a preliminary notice of which attention was directed in these 
pages a short time ago, has lately made its appearance.” In addi- 
tion to the interesting observations already noted, it may be 
remarked that Mr. Haworth finds the nature of the plagioclase in 
the porphyrites from this region to be in no way connected with the 
presence or absence of quartz in the rocks. A more basic feldspar 
is sometimes found in a porphyrite containing free quartz, than 1m 
one in which no quartz is visible. The ground mass of a certain 
class of the porphyries resembles in structure the appearance known 
as peecilitic. This is due to the inclusion of small particles of ma 
in quartz.—The elæolite-syenite? from the middle Transvaal, Sout 
Africa, consists of apatite, sphene, augite, hornblende, me ome 
all the 
older constituents. The augite occurs in two generations. he 
acmite. It contains both alkalies and manganese. The nepheline 
is for the most part fresh; but in some cases has undergone alter. 
ation into zeolites.—A typical chlorite-schist has been discov ve 
by Cathrein‘ at Gerlos, in the Tyrol. In a muscovite-quar 
1 Neues Jahrb. f. Min., ete., 1888, ii., p. 67. 
1 Inaug. Disser., Johns Hopkins dalv., 1888, and Amer. Geologist, 
Tre June, 1888. 
3 E. A. Wülfing. Neues Jahrb. f. Miner., 1888, ii., p. 16. 
* Verh. d. k. k. Geol. Reichsanst. 
