24 G. W. Hawes—Albany Granite, 
crystals that form the granite have become smaller with the ex- 
ception of the large feldspar crystals, which are in consequence 
more conspicuous. Ata distance of sixty feet a tendency in 
the quartz to assume crystalline forms is noticed, and the rock 
begins to appear porphyritic. At fifteen feet from the contact 
with the schists, the quartz is found in well-defined dihex- 
agonal pyramids, as large as peas, and these with the Carlsbad 
twins of orthoclase are imbedded in a ground mass no longer 
resolvable by the unaided eye or lens. Upon the contact the 
ground mass is nearly black in color, flinty in texture, and 
apparently homogeneous. The Albany granite has become a 
with two exceptions. The Carlsbad orthoclase twin crystals 
and the zircon crystals have the same shape and size in all 
* The Bodegang previously referred to is filled with quartz porphyry which 
however has a coarser ground mass in the center. , 
In the Vosges the granites which have altered the slates are upon their side 
usually unaffected. At one spot however in the Weibermattenthal the granite 
became porphyritic upon the contact. Rosenbusch, Die Steiger Schiefer und ihre 
Contact den Granititen von Barr-audlan und Hohwald, p. 156. 
In the Pyrenees near Case de Brousette a contact occurs between clay slate and 
a porphyry which farther south gradually changes into granite. Zirkel, Zeitscbr- 
d. d. Geol. Ges., 1867, p. 106. 
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