366 B. K. Emerson — " Bemardston Series" of 



it is, the fragments on the surface can be safely used to deter- 

 mine the rock below. The series wraps round the argillite, 

 and uniformly dips away from it, generally at low angles, at 

 first south, and then for a long distance southeast; then it 

 swings sharply round, crossing the State line with dips a little 

 north of east, making thus a great bend to the westward as it 

 crosses the town of Yernon. I have not been able to prove 

 the existence of folds or overturns, and the present position of 

 the beds seems to be best explained as the result of very 

 extensive faulting. 



(a.) The Argillite. — I have assigned to the argillite the 

 broad area marked " Coos " upon Professor Hitchcock's map, 

 to which he also assigns the slates of the Bemardston series, 

 because I have found that the boundary between it and the 

 argillite to the west, as given upon that map, has no justifica- 

 tion in any physical change in the character of the rock where 

 it is drawn, and the argillite can be traced unchanged up to 

 and dipping beneath the quartzite next described. It is true 

 that minute scattered garnets and very small staurolites are 

 found sparingly in the rock in some places in this area, and 

 these seem to have been relied upon by Professor Hitchcock 

 in making the assignment of the rocks to the Coos ; but the 

 same garnets can be found at times in the undoubted argillite 

 in West Mountain, and these, and the same minute staurolites, 

 occur in the center of the Whately argillite, and both the 

 minerals are very different from their representatives in the 

 Coos group. Both in macroscopical and microscopical struc- 

 ture, the rock remains quite constant up to the quartzite, and 

 in its liner grain, its darker color, its excessive contortions, and 

 its abundant and large quartz veins, it is well distinguished 

 from the slates of the higher series. 



(c.) The mica schist and hornblende &er7s.— Resting on the 

 basal quartzite, and dipping from it with low angle to the 

 south, southeast and east successively, as it. folds around con- 

 formably with it, is a broad area of mica schist, with several 

 bands — probably five — of hornblende rock, and a central band 

 of gneissoid quartzite. From the unequal rigidity of these 

 rocks, they are thrown into great confusion, and from the 

 similarity of the rock in the separate bands, the tracing of 

 them is very difficult, and as they are placed upon the map, a 

 greater regularity appears than exists in the field, many bands 

 being made up of the slightly shifted portions of what was 

 originally one, and many minor faults being of necessity 

 neglected. 



In general the schist is, below, finer grained, more slaty, 

 with small development of the transverse mica, without stauro- 



