Cape May Formation — Description. 163 



same amount, the flow of water would not be • affected except 

 in the part drowned. But in this epoch, deposition took place in 

 those parts of the valleys which were well above sea level, so 

 that something besides a lower stand of land was involved. 



If with the lower stand of land, the upper parts of streams 

 were depressed more than the lower parts, the flow of water 

 would be more sluggish throughout, and deposition favored. 

 Again, a change of climate might have been adequate, in itself, 

 to cause deposition, — especially such a change as went with the 

 glacial epoch. The cold which glaciation implies would have 

 reduced appreciably the vegetation of the region bordering the 

 ice, and no part of the area here under consideration was far 

 from its edge. The reduction of vegetation would have favored 

 erosion outside the channels of the streams, especially in a region 

 such as southern New Jersey, where the surface formations are 

 chiefly gravel, sand, marl, and clay. Even if precipitation was 

 not increased, more of it doubtless fell as snow, and the melting 

 of the snow at the season when the ground is least protected by 

 vegetation, would have favored erosion. In this way it is be- 

 lieved that much detritus was gathered from the slopes and car- 

 ried down to the valleys where deposition took place. If at the 

 same time the lower ends of the valleys were depressed, their 

 lower parts were silted up, the aggradation would have checked 

 drainage above, and so have favored deposition above the lower 

 ends of the valleys. This might have been effective far up the 

 valleys of streams with low gradients, like those of southern New 

 Jersey. 



DISTRIBUTION. 



In valleys. — In keeping with this conception of the deposits 

 of this time, the sands and gravels which represent it are found 

 at low levels about the coast and in the lower ends of the valleys, 

 and they extend far up the valleys to elevations of 140 or 150 

 feet along streams which have their source in the higher parts 

 of the Coastal Plain. The formation is named from the penin- 

 sula or cape at the southern point of the State, for all the ma- 

 terial of Cape May, so far as exposed, belongs to this epoch. 



