48 NEW YORK STATE MUSEUM 



It is generally medium grained with scattering labradorite plieno- 

 crysts, and weathered brown. 



A locality of special interest is a cliff on the southern border of 

 the area three-fourths of a mile east of the summit of Sunrise 

 notch. Most of this rock is very gneissoid and only moderately 

 gabbroic Whiteface anorthosite, a little finer grained than usual. 

 Its mineral content is given as no. 20 of table i. Within this rock 

 there is a wide band of fine-grained, very gneissoid, gray rock with 

 a reddish tinge due to numerous tiny garnets. The composition of 

 this local band, given as no. 10 of table 3, causes it to be classed 

 with the Keene gneiss, the high content of microperthite and ortho- 

 clase showing it to have strong syenite affinities. Its contact 

 against the anorthosite is not very sharp. Evidently a dike or 

 tongue of the Keene gneiss magma here intruded the Whiteface 

 anorthosite near its border, and the temperature was high enough 

 to cause fusion of the anorthosite walls of the dike or tongue. 



The small area of Whiteface anorthosite one-third of a mile 

 north of the locality just described, presumably represents a body 

 of anorthosite which failed to become assimilated by the syenite 

 magma. 



Area west of East Kilns. This area, -between i and 2 miles 

 west of East Kilns, shows certain interesting and important fea- 

 tures. Much of the rock, whose composition is given as no. 41 of 

 table 3, has strong syenite affinities because of its high orthoclase 

 content. 



Near the middle of the northern boundary, syenite contains 

 Whiteface anorthosite inclusions as bunches, lenses and bands 

 from 2 or 3 inches to several yards long, the boundaries of the 

 inclusions usually not being very sharp. Evidently very little 

 assimilation of the anorthosite took place here. 



Along the northwestern side several ledges are very gabbroic in 

 appearance, in some places very gneissoid and in others not. 

 Locally there is intimately associated syenite and Whiteface anor- 

 thosite. Apparently these ledges show the effects of partial diges- 

 tion or assimilation of anorthosite by the syenite magma. 



Along the main brook, for one-fourth of a mile after it enters 

 the area, there are good exposures of homogeneous, scarcely gneis- 

 soid Keene gneiss, with the phenocrysts of labradorite not so large 

 as usual. This rock, whose composition is given as no. 41 of 

 table 3, has strong syenite affinities because of its high ortho- 

 clase content. In this portion of the area, syenite magma quite 

 certainly completely assimilated more or less anorthosite. 



