474 C. H. HITCHCOCK — AMMONOOSUC DISTRICT, NEW HAMPSHIRE 



sions of slate. I have noted this fact specifically in the auriferous con- 

 glomerate on Smith brook in Lyman, in the conglomerate near Mormon 

 hill, and remarkably large pieces in the Coos conglomerate in the north 

 edge of Landaff (Baptist church). The schist inclusions at North Lisbon 

 may have come from slates. All the conglomerates, except those farthest 

 east, abound in fragments of the white Lyman schist. The green Lisbon 

 schists occur sparingly. 



It seems proved, therefore, that all these conglomerates are closely re- 

 lated to one another. Stratigraphically they overlie the fossiliferous 

 limestone of the middle Upper Silurian, and also the sandstone of Fitch 

 hill, from which' last they are separated by a few feet of argillite. 



Areas of Argillite 



Enough has been said of the Blueberry Mountain main range of 

 argillite — a possible Siluro-Devonian basin, extending from Bath to 

 Littleton, 20 miles. It is traversed by veins of auriferous quartz. At an 

 artificial tunnel in Lyman this rock has been pierced for nearly 700 feet, 

 and gives as much evidence of disturbance by folding and faulting as the 

 auriferous conglomerate. I can not find marks of strata distinct from 

 those of cleavage. At two localities there is a resemblance to ribbons of 

 color produced by a minute bending and faulting. At Kilburns rest in 

 Littleton the slates have been shattered as if by a crusher, and the frag- 

 ments reunited by some sort of adhesion. Other ledges have been 

 faulted slightly since the ice age. Crystals of staurolite are wanting in 

 this area, though small garnets are sometimes seen. In my report I 

 made the presence of staurolite indicative of a difference in age. It 

 seems to be generally believed that this is not a necessary distinction, 

 because the secondar}^ minerals may be developed by metamorphism. 



• 



If so, the next argillitic area to be mentioned, on the east side of the 

 Ammonoosuc, must be regarded as a repetition of the first. It is 7 or 8 

 miles in length, less mountainous, cut deeply by the south branch, ter- 

 minated at the north end by the great eruption of Bethlehem granite, 

 and, after continuing through Lisbon, ending in Landaff like a synclinal. 

 It was called Coos slate in the report, it is easy to find at several local- 

 ities clear evidence of banded strata crossing the cleavage planes at right 

 angles. While the cleavage planes dip generally from 60 to 70 degrees 

 to the north of west, the strata at the western edge of the argillite dip 

 from 25 to 30 degrees southeasterly. One locality is along the gulf road 

 from Lisbon to Breezy hill, and another at the crossing of Salmon Hole 

 brook, by the carriage road, a mile east of the Sugar Hill railroad station 

 (see plate 42, figure 6). Slender staurolites are found in it west of Pearl 

 lake, and especially at a bend in the south branch, 3,000 feet east of 



