LITCHFIELDITE IN PLACE 467 



Petrographically, the litchfieldite of the two injections can not be dis- 

 tinguished from the normal rock of the boulders described by Bayley. In 

 both cases cancrinite and sodalite are present as quite subordinate acces- 

 sories. The museum specimens exceptionally charged with either of these 

 minerals have been derived from local schliers in the boulder rock and do 

 not represent typical litchfieldite. Apatite occurs in the ledge litchfield- 

 ite, though not reported by Bayley as in the boulders ; on the other hand, 

 zircon has not been identified in the ledge rock. Otherwise Bay ley's de- 

 scription applies essentially also to the rock in place. The ledge rocks 

 are strained and granulated to about the same degree as that illustrated 

 in the boulders. 



Soda-syenites 



At locality 7) is a large exposure of a nephelite-free, alkaline syenite 

 w^hich is doubtless intrusive into the schists surrounding it. The outcrop 

 measures 30 meters from east to west and approaches 10 meters in width. 

 At locality C a much larger body of a closely similar syenite sends tongues 

 into and incloses blocks of the schists. This intrusive body is at least ' 

 300 meters long and 75 meters wide. Its longer axis is parallel to the 

 bedding of the sedimentary schists, here vertical and striking north 60° 

 to 80° east. At one visible contact the eruptive is concordant with the 

 schists, and there can be little doubt that it is a thick lens injected along 

 the plane of schistosity. About 100 meters northwest of locality 5 is a 

 third lens of the nephelite-free syenite, about 20 meters in maximum 

 thickness. Judging from the distribution of glacial erratics composed 

 of the soda-syenite, several other small intrusions not cropping out must 

 be assumed in the area of figure 1. 



These syenites are medium grained to coarse, often pegmatitic, and 

 generally charged with large bent foils of biotite, identical in habit with 

 the mica of litchfieldite. The feldspars are also the same, with a specially 

 noteworthy development of untwinned, metamorphic albite in the crush- 

 mosaics like those seen in the litchfieldite. 



The large body at C is made up partly of this biotitic syenite, partly 

 of an amphibole-bearing mica-free phase which appears to graduate into 

 the former through mica syenite with accessory amphibole; the feldspars 

 and subordinate accessories remain the same throughout. The amphi- 

 bole, a new variety, is powerfully pleochroic, with tints of deep grayish 

 blue and greenish yellow. The axial plane is perpendicular to the plane 

 of symmetry. The extinction in the prismatic zone is everywhere sensibly 

 zero. The amphibole obviously belongs to the alkaline series, and in its 



