404 MESOZOIC TIME. 



were formed in the course of the folding of the Appalachians, or 

 earlier. The formation is made partly Jurassic, because this appears 

 to be indicated by the fossil plants obtained from some of the beds. 

 They lie unconformably on the folded crystalline rocks, and thus show 

 that they are subsequent to them in age. On the map, page 144, the 

 narrow areas are obliquely lined from the right to the left. The prin- 

 cipal of them are : — 



(1.) The Acadian area, situated along the western margin of the 

 peninsula of Nova Scotia, and about 150 miles long; also in Prince 

 Edward's Island. 



(2.) The Connecticut Valley area, extending from New Haven on 

 Long Island Sound to Northern Massachusetts, having a length of 

 110 miles and an average width of twenty miles. 



(3.) The Palisade area, commencing along the west side of the Hud- 

 son River, in the southeast corner of New York, near Piermont, and 

 stretching southwestward through Pennsylvania, as far as Orange 

 County, Virginia, about 350 miles long. 



(4.) The North Carolina area, commencing near the Virginia line, 

 and extending through North Carolina, over the Deep River region, 

 120 miles long. 



The map of Pennsylvania, on page 310, shows the position of the 

 area in that State, it being distinguished by the same oblique lining as 

 on the general map. It takes the same westward bend with the Ap- 

 palachians of the State, being parallel with the mountains. 



Kinds of rocks. — The rock is in general a red sandstone ; often a 

 conglomerate with the stones sometimes one to two feet in diameter, 

 and rarely a black bituminous shale ; occasionally impure limestone, 

 or limestone conglomerate. The sandstone is largely a granitic sand- 

 rock made of pulverized granite or gneiss. There are often sudden 

 transitions from sandstone to coarse conglomerate ; and, in many 

 places, thin layers of large stones lie in the finer beds. Many layers 

 are obliquely laminated, in a coarse style, showing, like the occurrence 

 of the conglomerate, the action of powerful currents in the deposition 

 of their material ; while other portions are thinly laminated, indicating 

 regions of still waters or eddies ; and still others are fine, even-grained, 

 brownish-red sand-rock, making an excellent building stone, and often 

 called freestone — as at Portland, in Connecticut, and near Newark, in 

 New Jersey. Near Richmond, Va., and along Deep River, N. C, 

 there are valuable beds of bituminous coal. The coarser conglom- 

 erates abound on the western sides of the areas from New Jersey 

 southward. The Potomac pudding-stone marble of Point of Rocks, 

 Maryland, is of this formation. 



