248 The American Geologist. October, ih96 
of a granular mixture of fresh hornblende, feldspar, biotite 
and quartz. The feldspar is mostly plagioelase, although 
microcline and orthoclase are also present. A few small apa- 
tites were noticed, and also granular titanite, sometimes en- 
closing cores of magnetite, evidently titaniferqus. (Uilorite 
is present, but rare. A few of the plagioelase grains show 
dynamic action, and the dark ferro-magnesian constituents 
are at times much corroded. 
DioKiTE Dikes. 
Dike at I4. This intrusive consists normally of a moder- 
ately fine-grained diorite with hornblende, much plagioelase 
and some biotite, having a holocrystalline structure. This 
structure may become schistose at times, when a marked in- 
crease in hornblende or even biotite is noticed. The rock also 
assumes a line-grained phase at points along the edge of the 
dike (Uf). 
Playioclase, the important feldspar, is often slightly kao- 
linized and rarely shows any wavy extinction. A prominent 
feature is the universal presence of inclusions, which are 
sometimes so minute as to appear as dust-like masses and at 
other times consist of small dots and rods, often arranged in 
rows of a dozen or more. These various inclusions are almost 
identical with those described by the late Prof, Williams in 
the feldspar of norites of the Cortlandt series near Peekskill, 
N. Y.* Rutile needles and hexagonal plates of mica are also 
included. One section (14f) showed small needles of an un- 
determined mineral, with inclined extinction, occurring in the 
plagioelase. f 
Some of the plagioelase seems to have formed before the 
hornblende (lid), as shown by the inclusions of the former in 
the latter. This reversion of the usual order of crystalliza- 
tion has also been noted by J. F. Kemp in the C/Ortlandt rocks 
at Rosetown, N. Y.;|: 
Orthoclase is rarely present. 
Hornblende is wery abundant and is usually in the form of 
rather broad plates with corroded outline. The alteration is 
*Amer. Jour. Sci. (3), xxxi, 26. 
fThese may be pyroxene microlites similar to those noted by J. F. 
Kemp as occurring in the labradorite of the Adirondack anorthosites. 
Bull. Geol. Soc. Amer., v, 216. 
JAmer. Jour. Sci. (3), xxxvi, 251, 1888. 
