6 RURAL ^EW YORK 



valley. Rather it may be characterized as a low 

 region but the surface is exceedingly irregular. It is 

 a series of undulating to broken hills set apart by an 

 irregular network of valleys more or less filled with 

 glacial debris and in which most of the streams follow 

 a tortuous and often sluggish course. These state- 

 ments apply especially to the Hudson Eiver section. 

 The Hudson Eiver itself occupies a very narrow, low- 

 walled, mostly rock trench with almost no bottom 

 land along its course. The Hudson gorge and valley 

 extend out to sea in a southeast direction seventy-five 

 miles beyond New York City. At the present time, 

 tlie tide reaches up the river 150 miles to Troy. This 

 situation is explained by the fact that in earlier geo- 

 logical times the region stood at a much higher eleva- 

 tion and the general system of valleys was then 

 formed. Subsequently, during the glacial epoch, the 

 region was depressed. Later, it was raised but not to 

 its former position. Borings in connection with the 

 development of the Ashokan water supply for New 

 York City in the Catskills showed a trough eroded in 

 the rock more than 1000 feet below the present sur- 

 face of the Hudson Eiver near Newburg, where the 

 inverted svphon of the canal crosses the channel. 



In the Palisades region below Newburg, the rocks 

 rise for the most part precipitously from the water's 

 edge. Farther north, that is half way to Albany, the 

 rise is less abrupt and bold but still of a rugged hilly 

 form. Beginning near the north line of Dutchess 

 County and extending northward, a gently undulat- 

 ing plain fringes the river but at an elevation of sixty 



