.\1-|'AI.A< 111 AN \|(il STAINS. 40 



A niiiarkaMf Ifatiiic <»r this system is a large central 

 \allrv running its eiitiu' leii^^lh from north t(i south, called 

 l»y Mr. Ko,uers, the (Jreat Ai)j)alaehiaii N'alley. 



It he^rins with the hasin of l.ake ( 'haiiii>laiii ami the val- 

 Icv.ofthe Hudson: in I'ennsylvania is known as the Kit- 

 latinny or Cumberland Valley: in \'ir«;inia, the Great \'al- 

 lev widenin<; out at last into the \alley of East Tennessee. 



But wliilr there i< this coutiimity. there is also much of 

 contrast . 



Tiie Apitalaehian system naturally divides into three 

 sections, each di tiering in many respects from the others. 



The first division extends from Gaspe to tlie Hudson, 

 mainly a single range, known in its different portions, as the 

 Canadian Highlands, Green Mountains, and Highlands of 

 New York, with the outlying groups of Katahdin in Maine, 

 and the White Mountains of New Hampshire on the east, 

 and the Adirondacks of New York on the west. 



Thi> chain is broken through Ijy the Hudson and Mohawk, 

 and attains its minimum of altitude and width, in the vicin- 

 ity of these rivers. 



Four himdred feet rise in the waters of the ocean would 

 .separate all tliis northern division from the American conti- 

 nent ; one hun(h-ed and forty feet would make an island of 

 all'New England and the British possessions as far as Gaspe, 

 for the bottom of the valley occupied by Lake Cham])lain 

 and the Hudson does not, anywhere, exceed this level. 



This was the lir-t i-oute across the country traversed by 

 canal and railroad. Jt seems probable that this de)»ression 

 i< the result of a subsidence of that portion of the system, 

 at a period subsequent to that of its original elevation, and 

 it i< i)roved that all New .h-rsey. from Cape Ahiy to New 

 \n\k. is midergoing a gradual subsidence. Along portions 

 ot the coast the remains of submerged forests are now visi- 

 ble- under water, and the soundings of the Coast Survey have 

 determined the existence of an ancient channel, a continu- 

 ation of tiiat of the Hmlson. leading far out to .n-a. which 

 could have been excavated only wlun the ]>resent bottom 

 of the sea occupie-d a higher level. 



