490 W. H. HOBBS — LINEAMENTS OF ATLANTIC BORDER REGION 



mon direction (north 5 degrees east along the Hudson river), but the 

 east base of the Green mountains also can be followed on the govern- 

 ment map as a distinct line having this direction from lake Memphre- 

 magog on the north to the latitude of Springfield, Massachusetts, on the 

 south, be} r ond which point southward the line is continued as the ap- 

 proximate western border of the Newark area of the Connecticut valley 

 with the crystalline uplands (VI). 



Franconia line. — To the east of the Connecticut we find a line formed 

 by the Thames and Little rivers. This line is continued across the 

 White Mountain mass of New Hampshire as the famous Franconia 

 notch, which, with its continuation, the Pemigewasset river, extends 

 along this direction from the Profile house on the north to West Thorn- 

 ton (about 20 miles) on the south, as an almost rectilinear furrow 

 through the mountains (VII). Again, north of the notch this line is for 

 30 miles or more the course of the upper reach of the Connecticut river. 



Kennebec, Penobscot, and Saint Johns lines. — Eastward still the same 

 direction is brought out in the courses of the Kennebec (IX) and the 

 Penobscot (X) in Maine. Without attempting to follow in detail the 

 course of these lines, we may note the one (XIII) which, skirting the west- 

 ern shoreline of Nova Scotia, passes through a cleft (Petit passage) in the 

 trap ridge of the northwest margin and is followed to the north in the 

 zigzagging course of Saint Johns river.* Along the course of Saint 

 Johns river this line is one along which formations abruptly end.f 



Within the region of New England and the provinces the lines of the 

 series are spaced with an approach to uniformity. The Hudson-Cham- 

 plain line (V), the western Connecticut line (VI), and the Franconia line 

 (VII) are, in the latitude of Boston, something over 40 miles apart. 

 This is also the approximate distance separating in the same latitude the 

 Kennebec (LX) and the Penobscot (X) lines, while the space between the 

 Franconia and Kennebec lines is a double interval. 



Meridional fall line. — West of the Hudson the line of this series which 

 appears prominently on the map is, however, much farther separated 

 from the Hudson-Champlain line. This line (IV), from the Great falls 

 of the Potomac, passes southward from Richmond and Weldon as a 

 section of the fall line described by Powell, and, as shown by him, is the 

 boundary line of the crystalline rocks on the west, with the Cretaceous 

 and Eocene on the east. Near the Great falls of the Potomac this line 

 follows a dike of Newark trap and crosses the state of Pennsylvania a 

 little west of but parallel to the course of the Susquehanna. To the south 



*By the Gaspereaux, the T-like arms of the Mirimichi and the Nepisiquit, the line is carried 

 across New Brunswick to the Saint Lawrence. 



fSee in "Acadian Geology" (1868), a geological map of Nova Scotia, New Brunswick, and Prince 

 Edward Island, by J. W. Dawson. 



