HOOSAC AIOCNTAIN. 



59 



cretionary forms, arc, first, the shape and distribution of these forms (well 

 shown in the figures) and the alternations parallel to the stratification (deter- 

 mined by contact with other rocks) of bands of coarse and fine material; 

 second, the diverse nature of the pebbles in the same rock (blue quartz, 

 white quartz, granulitie rock, granite, etc.); and, third, the frequent transi- 

 tions in the field into quartzite and quartzite-conglomerate. The production 

 of at least part of the mica, feldspar, and quartz of the cement in situ has been 

 indicated, and also the effects produced bv crushing. 



THE HOOSAC SCHIST. 



The next member of the series is the albite-schist (see Figs. 21, "22, 23, 

 and PI. vin, k), which conformably overlies the conglomerate on top of 



Fig. 21.— Albite schist (Hoosac schist). Dump, Central Bhaft. One-twelft 

 This is the type with thin flat <|iiartz layers (the white streaks) and ge 



1 size. 

 npling. 



Hoosac mountain, extending northward for miles into Vermont. On the east 

 it extends southward along the east side of the conglomerate and on the west 

 in a narrow band along the west slopes of the mountain, curving around so 

 as to almost join that on the east. In Hoosic valley masses of these schists 

 occur adjoining the Stoekbridge limestone and then lying between it and 

 the Hoosac gneisses of the Vermont formation. In the tunnel a band occurs 

 several thousand feet wide (see PI. v, Profile in) between the west baud 



