Metamorphic Upper Devo7iian Hocks. 363 



stone on the Williams farm, and I have no doubt that they 

 were formerly connected across the valley. Higher up, the 

 rock is a pudding stone with rounded quartz pebbles up to 

 100 mm in length, but mostly 20-30 mm long ; the abundant 

 quartz sand paste, which wraps round them, cleaves into thick 

 layers coated with muscovite scales and iron rust, so exactly 

 like the upper quartzite of the Williams farm, especially the 

 conglomerate layer, that it is difficult to avoid the conclusion 

 that they are also parts of a single stratum. Calculated upon 

 its average dip of 20° the thickness of the bed is 123 meters, 

 which is only a rough approximation. 



In the field south of A. Gr. Chapin's house is an interesting 

 outcrop. The rock is here jointed with almost mathematical 

 accuracy, into acute rhombs, the joint-planes passing through 

 the quartz pebbles ; and the latter are finely compressed, and 

 indented one by another. The rock here carries garnets 5 mm 

 across. The rock is unchanged across Dry Brook for a long 

 distance to the northeast, when it crosses the last road ; but 

 once over the range (J. M. Picket) at a point where the brook 

 makes a loop across the road, the pebbles are flattened out into 

 thin disks, resembling the small lenses of quartz common in 

 crystalline rocks, making it almost doubtful if they may not be 

 •of secondary origin — a doubt which does not extend to the 

 range described above. In the woods, southwest of this point, 

 the rock in some beds is in appearance a fine-grained biotite- 

 gneiss, with large garnets surrounded by a broad annular color- 

 less space, in which the biotite is wanting ; and in following 

 the band farther north, the pebbles grow smaller, and where 

 it crosses the State line it is below a thin-bedded biotitic 

 quartzite, above a muscovitic quartzite ; and in some layers 

 the muscovite becomes abundant and wraps around pencils of 

 quartz, so that the rock obtains a rude columnar or ligniform 

 structure. It has here an apparent thickness of 107 meters. 



At the point already mentioned on the grist mill road (J. M. 

 Pickett) where the brook makes a short loop across the road, 

 -at the south bridge is a fine section in a high bluff, west from 

 the bridge. The conglomerate strikes N. 45° E. and graduates 

 downward through fifty feet of quartzite into fine micaceous 

 quartzite and this into flat argillite with minute transverse 

 biotites. The whole is well exposed and plainly conformable. 

 Its dip increases from 22° at the south end to 45° at the north 

 end, where the upper portion of the bed has this high dip, 

 while the lower portion runs up on the argillite with the low 

 dip of 20°. It thus folds around and dips away from a great 

 promontory of the argillite ; and it is blackened in many places 

 by a remnant of the argillitic material. 



