3l6 STRATIGRAPHICAL GEOLOGY. 



Coos Grouj 



Two areas referable to the Coos group constitute much of the eastern 

 boundary of the tract now being described. The first enters Littleton 

 from Dalton, crosses the Ammonoosuc near Littleton depot, and rises 

 into Eustis hill. The north end is about two and a half miles north-east 

 from the Littleton line, dipping near J. Ouimby's in a westerly direction. 

 There is a considerable hornblende schist between the mica schist and 

 the gneiss. The band is about a mile wide where it enters Littleton 

 upon Mann's hill. The common or Lake gneiss borders it on the east 

 in Dalton, but in Littleton it comes in contact with porphyritic gneiss, 

 and on the west at first the Huronian. Further along it may touch the 

 Helderberg, but for two or three miles it borders gneiss, especially on 

 Oak hill and at the village of Littleton. At A, Annis's the dip of the 

 mica schist is 70° N. 37° W. Part of these ledges north of Mann's hill 

 are calcareous, reminding one of the calciferous mica schists of Vermont. 

 Towards the crest of the hill and the western border of the formation, 

 the dip is 70° N. 52° W. Beds of hornblende occur in it, also. On the hill 

 west the dip is 70° N. 70° W. of mica and hornblende schists. Another 

 dip is 30° in the same direction, in ledges containing many staurolites 

 and garnets. There are a few feet thickness of granite associated with 

 the staurolite beds near Annis's. A mile farther south, near the road 

 turning to Smith's slate quarry from Mann's hill, the mica schists dip 

 80° N. 55° W., and also west. Where the formation crosses the road 

 near P. C. Wilkins's, the strike of it is N. 22° W, It was noticed that 

 the layers were somewhat twisted, and contained large hornblendic nod- 

 ules. It seems therefore to run athwart the underlying Lake and porphy- 

 ritic gneisses in an unusual direction, and, of course, unconformably. The 

 mica schist then proceeds southerly to Scythe Factory Village. It out- 

 crops in two or three places along the railroad on the east bank of the 

 Ammonoosuc. One ledge of it, by a mill-dam, exhibits the dip 75°-8o° 

 N. 22° W. Three fourths of a mile east on the railroad there is an iso- 

 lated outlier of it. Opposite the new scythe factory the micaceous quart- 

 zite dips 80° N. 37° W. With it are intcrstratificd argillaceous bands, 

 sometimes wrinkled. The gneiss crops out at the second dam at Scythe 

 Village. Perhaps a fourth of a mile above, on the railroad, the micaceous 



