NEW YORK. 



75 



extends 500 feet below the level of the ocean. Its bed is a deep chasm in the Laurentian or 

 Primitive rocks. On the west side, where the mountain ranges reach it, the slope is abrupt, but on 

 the east side it is longer and more gradual. At many places the lake is bordered by steep banks of 

 blue and yellowish brown clay and yellowish brown sand, rarely over 15 feet thick, but its greatest 

 height is 100 feet at Burlington. It contains marine fossils in the mixture of clay and sand, but 

 none in the clay beneath. This drift formation extends north to the mouth of the St. Lawrence 

 River. In Albany County it is an immense mass and is known as the Albany clay. 



52. From Dresden to Port Kent, 67 miles, the Laurentian hills are the western boundary of the 

 valley of Lake Champlain. But at many points this mountain ridge recedes from the lake, leaving 

 nooks and valleys, in which are patches of 3 c. Chazy and 4 a. Trenton limestone along the railroad. 



53. The magnetic iron ore mines back of Port Henry are worth a visit, the bed of the ore being 

 more than 100 feet thick. The mining of these heavy beds is on a grand scale. 



54. From 51 Westport to 77 Port Kent, the formation, according to Dr. Hunt, is 1 c. Norian or 

 Upper Laurentian. 



55. At the village of Essex, on the lake and between Wallonsburg and Willsboro stations, is a 

 bold bluff, 100 to 200 feet high above the lake, of 3 c. Chazy limestone. 



56. The Adirondack Mountains commence at Little Falls, rising suddenly from the Mohawk 

 Valley, and run northeast to Port Kent on Lake Champlain. The most elevated peak, Mount 

 Marcy, is 5,467 feet high, the summit being just upon the region of perpetual frost. There are four 

 other peaks 5,000 feet high, each distant about 6 miles from the other. This group of Adirondack 

 Mountains is the culminating point of the State around the sources of the Hudson, Ausable, 

 Racket and Black Rivers, and dividing the north half of the State into two separate geological 

 basins. They are directly west of Westport, several miles to the west of the railroad. Only a 

 glimpse of one of them can be had from the railroad. In the Adirondack pass in Essex County, is a 

 perpendicular precipice or naked wall of rock 1,000 feet high and more than half a mile long. There 

 is not probably in the Eastern States an object of the kind so vast and imposing as this. 

 Emmons, 218. 



57. Stop at Plattsburg and visit the Ausable valley, which is interesting for the Ausable chasm, 

 where for at least two miles the Ausable River, a large and rapid stream, is compelled to flow 

 through a rocky gorge in the 2 b. Potsdam sandstone with perpendicular walls of 100 feet with a 

 width only varying from 20 to 40 feet. Here the linyula antiqua is found in great abundance, and 

 there is here a better development of the Lower Silurian or Cambrian rocks than in any other part 

 of the State. Emmons, 267. 



58. The 3 c. Chazy formation was named from this locality. See Note 55. Also as to Isle La 

 Motte see Note 67. 



59. The rock which forms Diamond Island in Lake George is a good example of 3 a. Calciferous. 

 Lake George is 30 miles long, H miles wide, and its surface is about 80 feet above tide water. 



