1895. ] NEW YORK ACADEMY OF SCIENCES. 85 
thus they show very irregular shapes as though they had been 
partially dissolved. 
Both the orthoclase and plagioclase are filled with countless 
numbers of included plates, rods and dots. Prof. Williams 
notes their resemblance to the trichites of certain volcanic 
glasses. Their irregularity of direction precludes the possi- 
bility of their being solution planes. SBzotite forms about one- 
half of the rock. It is green and strongly pleochroic, green to 
brown. The borders of the crystals are much corroded and the 
embayments are filled by quartz, which also fits the crystal. The 
ends of the individuals are frayed, but bending of the lamellz is 
rare. Muscovite is occasionally present and is sometimes in- 
cluded in the biotite. Hornblende is distributed throughout the | 
rock, but is less abundant than the quartz. It exhibits the 
same corrosion phenomena and quartz inclusions as the biotite. 
RutTitE NEEDLES IN QUARTZ, Q; CaucitE, C; Biotite, M. 
It is strongly pleochroic green to brown. Garnet is chiefly con- 
fined to the feldspathic portions of the gneiss. Tvtanite is 
present sparingly and occurs in the usual form or as clusters of 
rounded grains associated with the biotite. Pyrite, though 
present, is rare, and its disintegration often furnishes limonite. 
Rutile is finely developed in one section from the northern end 
of the area and its long needles pierce the quartz in every direc- 
tion. Infiltrated calcite occurs with it. Szllimanite also oc- 
curs in the schistose facies of the rock. 
The large amount of plagioclase present in the gneiss makes 
it too basic to be called a granite, and therefore the term gran- 
