THE HOOSA(J SCHIST. 69 



(•riiiii|iU'(l injiguetite-beariug inuscovite-schist (the inica often liydrated), 

 with an abunilauoe of tlie characteristic chlorite. 



The Hoosac schist appears in its usual development as a small por- 

 ))hyritic mica-schist or augen-gneiss It very closely resembles the Rowe 

 schist above, except (1) that it is darker and (2) that there are developed 

 in large numbers between the folia small, rounded grains of feldspar 2 

 to 3"™ across, so that the rock may be called a feldspatliic hydromica- or 

 sericite-schist. It contains the same chlorite as the rock above, though in 

 greatly lessened quantity. It thus differs decidedly from the granitoid 

 gneiss of Becket and Shelburne. Its feldspars have been determined by 

 Dr. J. E. Wolti' to be albite, though as a rule they lack the triclinic striatiou 

 on cleavage faces. The Hoosac and Rowe schists both strike N. 80° E. and 

 dip S. 60° at this point, so that the former dips beneath the latter. 



Going west, the boundary closely follows Mill Brook, arching round 

 to the northwest, and crosses the road to Florida, just south of where this 

 bi'ook crosses it, with a strike of N. 30° W., the Hoosac schist dipping 65° S. 

 beneath the Rowe schist. Still following the curvature of the brook, the 

 Hoosac schist strikes east-west south of C. Stafford's sawmill and dips 30° S. 

 beneath the Rowe schist, and the beds continue in this posture to the west 

 line of the town. Both the Hoosac and the Rowe schists are quite uniform 

 in character along this line. 



From the point of starting on the Deerfeld River, the boundary ])ends 

 around to the northeast, crossing the road from Monroe to Rowe just south 

 of the second brook-crossing and north of J. F. Brown's, with a strike of 

 40° E., the gneiss dipping 40° SE. beneath the schist. The Hoosac is here 

 a dark, subporphyritic, gneissoid biotite-mica-schist. Farther on it swings 

 round to run N. 20° E. and dips 20° E. and crosses the town line with the 

 most westerly of the roads from Rowe into Vermont, far to the west of the 

 point where upon the Vermont map the corresponding boundary is made 

 to cross the State line. The boundary is well defined in Massachusetts, and 

 especially well exposed where it crosses the Monroe-Rowe road in a ravine 

 visible to the east from the road. One sees to the left (northwest) the 

 whole hillside made up of the sulj})orphyritic gneiss (Hoosac), to the right 

 a dark, rusty, barren mica-schist (Rowe). 



The boundary of the Hoosac schist upon the Becket gneiss below is 

 found far beyond the border of the county to the west, and Dr. J. E. Wolff 



