PHYSICAL HISTORY OF NEW HAMPSHIRE. 5 15 



The Groton-Jaffrey range gives us Mt. Cardigan, 3156 feet; hills in Graf- 

 ton, nearly 2000; line of railroad from West Andover to Grafton, e'J^ 

 to about 900; Mt. Sunapee, 2683 ; Mt. Lovell, 2487. The southern end 

 of the area is more than 1000 feet above the sea. Fifth, there is a 

 group of islands in Warner, Salisbury, Webster, Hopkinton, and Hen- 

 niker, connected with the end of a promontory trending north-easterly 

 from the main range at Hillsborough. Sixth, a conspicuous line of 

 islands reaches from the north part of Webster, through Hopkinton and 

 Weare, into New Boston, over twenty miles long, and curved like a bow. 

 Seventh, possibly the Pelham and Seabrook islands, represented on 

 north-east range along the Massachusetts border. Eighth, it is notice- 

 able that the northern ends of the principal ranges sink beneath the 

 higher White Mountains, and have not yet been discovered to the north 

 of them in New Hampshire, though appearing east of Mt. Bigelow in 

 Maine,* ninety miles or more north-easterly from Mt. Carrigain. 



Additions during the Atlantic Period. 



At the close of the Atlantic Period the area of dry land was very 

 considerable, occupying fully two thirds of the present state limits. In 

 general terms, this area may be said to be central, the portions not filled 

 out being at the extreme north, on the sea coast, and along the Con- 

 necticut valley. The flanks of the principal porphyritic formation are 

 covered, and much of the space between the primitive islands is filled up. 

 The rock is also very commonly a gneiss. 



Several important events are indicated by the succession of deposits. 

 I give them as seems in best agreement with the facts as now understood. 

 First, and lowest down, are rather local deposits of a somewhat talcose 

 gneiss, receiving the name of Bethlehem group, from the locality where 

 its features are best displayed. Second, Winnipiseogee lake (or, for 

 short, Lake gneiss). I think this includes the Berlin and Manchester 

 ranges, mentioned in some previous publications. Third, Montalban, or 

 White Mountain series. Fourth, Franconia breccia group. It is not 

 needful to distinguish these formations on the map at present, and the 

 second of our map-illustrations merely shows the whole system as it 

 stands related to the preceding areas. 



* Proc. Amer. Ass. Adv. Set., vol. xxii, p. 212. 



