96 NEW YORK STATE MUSEUM 



intersected by widely spaced block joints. It is a dark green rock 

 of fine texture. It takes an excellent polish and is well suited for 

 monumental stone. 



Under the microscope the syenite from the latter quarry presents 

 some peculiarities not noted in the other occurrences. The chief 

 feature is connected with the ferromagnesian minerals which con- 

 sist mainly of a dark hornblende in the place of the usual green 

 diopside, and a smaller proportion of an orthorhombic pyroxene 

 that corresponds to hypersthene. Quartz is more abundant than 

 usual for syenite, occurring in small grains on the borders and in 

 the interior of the feldspars. The latter comprise microperthite, 

 microcline and oligoclase. The accessory constituents include 

 magnetite, zircon, apatite and titanite. The secondary products of 

 alteration are mostly chlorite, which is observed on the borders of 

 the hornblende, and limonite. The texture is even-granular massive. 



AUSABLE FORKS ANORTHOSITE AREA 



In the last few years some attention has been given to the quarry- 

 ing of anorthosite for building and monumental stone in the vicinity 

 of Ausable Forks. The anorthosite outcrops on the road from 

 Ausable Forks to Jay, beginning just south of the Stickney bridge 

 along the ridges that limit the valley on either side. 



The anorthosite belongs to the granulated type in which the 

 originally coarse feldspar crystals are only now and then evidenced 

 by unmashed individuals which in their surroundings of fine-grained 

 material appear like the phenocrysts in a porphyry. The color is 

 gray of light or medium tone while the uncrushed feldspars have 

 a dark greenish or bluish appearance and an iridescent play of 

 color. Some types contain much pyroxene, which is black in the 

 hand specimen ; the stone then is similar in appearance to a medium- 

 grained or coarse-grained granite. 



Most of the stone has been shipped from a quarry situated one- 

 half of a mile southeast of the Stickney bridge, formerly worked 

 by the Adirondack Granite Co. It is a small opening with a 

 face about 20 feet high, but the ledge extends fully 500 feet with a 

 face 50 feet high. The stone from this quarry was used in the 

 two first stories of the Locomotive Engineers Building in Cleveland, 

 Ohio, and in the Adirondack National Bank Building at Saranac 

 Lake. 



The rock is traversed at rather wide intervals by two sets of 

 vertical joints running N. 50 W. and N. 35 ° E. respectively. There 

 is a less marked division in a plane inclined about 30 from the 



