1893.] Mineralogy and Petrography. 1089 
In the northern Hardt Mountains, near Obbersweiler, Waldhambach 
and the neighboring regions, are biotite and hornblende gneisses that 
are probably squeezed granites, schists and graywackes, altered by an 
intrusive biotite granite and cut by other granites, a kersantite dyke 
cutting the intruded granite, and a sheet of quartz melaphyre overly- 
ng all these as a lava flow, the whole comprising the mass of the 
mountains. All these rocks Leppla* discusses in a recent article, de- 
scribing the melaphyre as consisting of a groundmass of plagioclase and 
quartz enclosing phenocrysts of feldspar, red olivine pseudomorphs, 
quartz and bastite. The quartzes are all surrounded by aureoles of 
augite, just as are the quartz inclusions in many basic rocks. 
In a monograph in the Kaiserstuhl in Baden, Knop' gives a general 
view of the geology, mineralogy and chemistry of this interesting vol- 
canic region, in addition to statements concerning its hydrography, 
botany, history, etc. All the minerals known to the region are de- 
scribed at considerable length, and over a hundred and fifty pages of 
the book are devoted to descriptions of its interesting rocks, phonolites, 
andesites, tephrites, basanites, basalts, limburgites among the volca- 
nics, and several others of sedimentary origin. The author treats the 
hill as an old voleano, and attempts to explain the variety in its pro- 
duets upon the Bunsen theory of mixed magmas. 
A two-mica gneiss? constitutes the principal rock of the Valley of 
Miñor, Provice Pontevedra, Spain. On the peninsula of Santa Marta 
it is cut by a diabase with faintly pleochroic augite. At Monte Gal- 
eñeiro the micaceous gneiss is replaced by a hornblendic variety in 
which the prominent amphiboles are glaucophane and a green variety 
opaque to light vibrating parallel to c. 
Chelius’ describes very briefly several occurrences of nepheline 
basalt from the Odenwald, Germany, and records the analyses of the 
red gneiss of Steinkopf, of the dark biotite gneiss of Bockenrod, of 
basalt from the Hiisengebirg near Urberach, of granite from the 
Melibocus massiv, and the results of silica and specific gravity deter- 
 Tünations of many other rocks from the same region, among whic 
may be mentioned malchite and alsbachite. 
 *Zeits. d. deutsch. geol. Ges., XLIV, p. 400. 
"Der Kaiserstuhl in Breisgau. Ein naturwissenschaftliche Studie von Dr. 
' 
A. Knop. Leipzig. W. Engelmann, 1892, p. 538 and fig. 89. 
"Quiroga: Actas d. 1. Soc. Esp. d. Hist: Nat., XXI, 1892, pp. 4 and 8. 
? Notizbl. d. Ver. f. Erdk. Darmstadt., IV, 1891, H. 12. 
43 : 
