542 PHYSICAL GEOGRAPHY. 



Plymouth, thence easterly to Squam lake, thence south 25 east over 

 the Winnipiseogee basin, thence easterly around the south end of Ossipee 

 mountain into Maine. Its course through Warren was southerly, and it 

 curved to the east in Rumney before reaching Plymouth. The variation 

 in direction corresponds with the course of an extensive valley. 



A somewhat similar set of striae follows the Northern Railroad from 

 Grafton to Andover, passing down the valley of the Blackwater river 

 between Mts. Kearsarge and Ragged. 



A very few local glaciers have been observed about the White Moun- 

 tains. Somewhat similar action, pushing gravel away from the bases 

 of large hills, may be observed in every part of the state. 



The terraces along the Connecticut and Merrimack rivers give us 

 information of the next marked feature in post-tertiary history. Care- 

 ful explorations along both these rivers show that the higher terraces on 

 both sides slope from the sources to the mouths, corresponding very 

 nearly with the fall of the stream. On the Merrimack the terraces in 

 Ashland and New Hampton are fully 800 feet above the ocean ; at 

 Franklin, 470; at Concord, 450; at Manchester, 250; and very much 

 lower in Massachusetts. Similar phenomena, though not so marked 

 within our limits, may be seen on the Connecticut. We conclude that 

 at the close of the glacial period, when the ice was melting rapidly, the 

 rivers filled their valleys even with the tops of the highest terraces. 

 The terraces are lower and broader nearer the ocean, but would require 

 the same amount of water to cover them. When the flow of water had 

 diminished, another set of terraces was formed, lower than and between 

 the first. In a similar way the terraces still lower were produced. 



During the terrace period the land was submerged certainly about two 

 hundred feet and more, if reliance is placed upon the argument from 

 maritime plants developed in a following chapter. Evidence of this state 

 of things is afforded by the discovery of marine shells and whales' ver- 

 tebrae in the coast region. The boreal character of the shells indicates 

 a climate like that of the present Gulf of St. Lawrence. During this 

 period the woolly elephant, wild boar, and primeval horse lived in the 

 wilderness in company with the aborigines, whose implements of stone 

 are so often plowed up in our fields. These wild animals have become 

 entirely extinct, and the savages have migrated. 



