Haworth on the Archaean Geology of Missouri. 393 
tivgesteine aus der Gneissformation des niederosterrichlschen 
Waldviertels," describes certain zones of feldspar material 
around plagioclase crystals which, if I understand his article, 
should be referred to a secondai-y growth during the second 
period of consolidation. The rock in which they occur is a ker- 
santyte. He divides the constitutent minerals into two classes. 
The first class includes basic feldspar, biotite, augite, olivine and 
quartz. He says that they were formed before the solidification 
of the rock mass and correspond to the "6l6ments de premiere 
consolidation" of F. Fouqut? and M. L^vy. The second class in- 
cludes plagioclase rich in soda, orthoclase, quartz, and pale-green 
hornblende, and correspond to the "Pigments de seconde con- 
solidation" of F. Fouque and M. L^vy. He then says: "These 
last constituents, which cannot be called secondary in the ordin- 
ary sense of the term, and which 1 have called constitutents of 
the second order, are at times most intimately associated with the 
above mentioned constituents of the first order; oligoclase and 
micropegmatite appear as zones of parallel growth around the 
andesine kernels of the first order,"' 
Again he says: "The feldspar crystals [of the 1 order] are 
united with the 'Zwischenmasse' [the material of the 11 order] 
by means of the oligoclase zones, "- and further; "Also the 
oligoclase zones pass directl}^ over into the micropegmatite, as 
is shown b}' the fact that the feldspar in the same extinguishes 
with the oligoclase zones of the adjacent feldspar crystal." ^ 
In the same year Karl Bleibtreu,* in a j^aper entitled, "Bei- 
trage zur Kenntniss der Einschliisse in der Basalten, mit beson- 
derer Berucksichtigung der Olivinfels Einschliisse," describes 
' p. 170. " Die letzteren Gemengtheile, die man nicht als secundar im 
gewohnlichen Sinne des Wortes bezeichnen kann, die ich deshalb als 
Gemengtheilen 11 Ordnung bezeichnen werde, sind mit den f ruber ang- 
efuhrten Gemengtheilen i Ordnung zum Theil auf das Innigste verbun- 
den; Oligoklas und Mikropegmatit erscheint als parallel fortgewachsene 
Hulle um die Andesinkerne 1 Ordnung." 
2 "Die Feldspathkrjstalle sind mit der Zwischenmasse durch die Oligo- 
klashulle verbunden." 
' "Auch setzen sich dieOligoklashullen hiiufig direct in Mikropegmatit 
fort, was daran erkannt wird, dass der Feldspathgrund desselben gleich- 
zeitigmitder Oligoklashulle benachbarten Feldspathkrjstalle ausloscht." 
♦ Zeitschrift der deutsch. geol. Gesel. 18S3. vol. 35. pp. 489-556. 
