34-8 STRATIGRAPIIICAL GEOLOGY, 



THE CONNECTICUT VALLEY BETWEEN HAVERHILL AND CLAREMONT. 



The second section of the Connecticut valley occupies the country 

 between the north part of Haverhill and Claremont, the limits being de- 

 signed to cover the territory south of the Ammonoosuc gold field as far 

 as to include the rocks of Mt. Ascutney, The following are the rock 

 formations in this area, arranged in the supposed order of their age: i, 

 Bethlehem gneiss; 2, Huronian, with three or four subdivisions; 3, Cam- 

 brian clay slate; 4, Coos quartzite; 5, Coos slates and schists; 6, Calcif- 

 erous mica schist; 7, Eruptive granites, including the Mt. Ascutney area, 

 which is partly composed of rocks older than Huronian. This territory 

 is about fifty-eight miles long and fifteen wide, including all of Vermont 

 that appears upon the map. That which lies in New Hampshire is 

 usually five or six miles wide. 



Bethlehem Gneiss. 



Regarding the narrow quartzite areas as the eastern border of our field, 

 it is clear that we have three isolated fields of Bethlehem gneiss on the 

 east side of the Connecticut, and perhaps the representative of another 

 among the foundations of the Ascutney formations. First, is the one in 

 Haverhill ; second, in Orford and Lyme ; third, in Hanover and Lebanon. 

 These all have certain features in common, and each has its peculiarities. 

 They are all repeated east of the quartzite areas in the Merrimack dis- 

 trict. 



HavcrJiill Area. This is confined to the town of Haverhill, with a 

 length of about eight miles and a width of three. Three sections cross- 

 ing it are represented. (Fig. 45 to Fig. 47.) In the most northern 

 there appear to be an anticlinal and a synclinal ; in the second, nearly 

 vertical strata throughout, which may therefore include one or more in- 

 verted axes ; and in the third, a synclinal. We have noted the following 

 varieties of rock in this area: Protogene; common gneiss; the same, with 

 an excess of black mica; granitic beds; hornblende schist; soapstone; 

 and limestone. The first ledges of gneiss seen south-east from Woods- 

 ville are inclined 40° N. 82° W. at a less angle than those farther east, as 

 at the soapstone quarry, dipping as much as 75° north-westerly. The 

 soapstone is from twelve to fifteen feet wide, with some pyrites scattered 



