198 J. D. Dana— Geological Relations of the 
This rock passes into a feldspathic kind (Bb), consisting 
almost wholly of the feldspars; and into a micaceous kind 
) ~aarne very muc bI ack mica with little hypersthene 
—a very common variety, often occurring close alongside of 
the Rs ae noryte. 
Although the noryte is generally a massive rock, it is occa- 
sionally distinctly gneissic in structure, and sometimes con- 
tains a few garnets. The schistose variety usually abounds 
in black mica, or contains more quartz than other varieties, 
and sometimes tag orthoclase. 
—True augitic rocks are sien common than 
liypersthene: rot although augite is sent in most of 
the massive rocks of the Cortland region. The chief kind (Ca) 
is pyroxenyte—consisting mainly of pyroxene or augite, with 
sometimes a little hornblende; it varies from a very coarse rock 
with the augite crystals half an inch across, to a fine granular 
kind. A greenish-gray granular variety occurs on Stony 
Point in its chrysolitic region. Another kind (Cd) contains 
varieties. Chrysoliti lands are cqoasiect teat rank 
D. The Micaceous.—The micaceous rocks are of two promi- » 
nent kinds. One (Wa) is like a coarse granite in aspect; but its 
feldspathic portion is chiefly triclinic, and quartz is sparingly 
present. It is pe uancdencras a soda-lime granite, although 
10 This rock looks like the noryte, we contains augite in place of hypersthene. 
If its feldspar is chiefly labradorite (a point yet in doubt), it does not differ in 
mineral constitution from doleryte or diabase, or a prominent part of the so-called 
bbro 
