VALLEYS. 13 



pally from the northern higlJands of New- York. It is this great extent of drainage from an 

 elevated wooded region which gives such a constant and regular supply of water, and it is 

 this which ensures its continuance. If, however, we look forward to a lime when a large pro- 

 portion of this wilderness sliall be under tillage, there is some probability that quite a different 

 state of things may exist in this respect, especially as it regards the Hudson. This river rises 

 whoUy under the shadow of forests, wild and uncultivated. If now those forests were to be 

 replaced by pastures or open fields of any description, the quantity of rain which now falls 

 would be materially diminished, especially during midsummer ; or if it should not be dimi- 

 nished, the evaporation from the surface would be greatly increased, so that the result would 

 remain the same under either condition. Less will flow in the natural channels, and the supply 

 for navigation may be so fax diminished as to prevent, or if not prevent, greatly impede the 

 navigation, and interfere with its employment for moving machinery, or the various purposes 

 to which water is appUed. 



The most important valley of the Second Geological District is the Champlain ; but only 

 a small proportion of this belongs strictly to New- York : still I have considered it as neces- 

 Sciry to investigate its physical as well as its geological relations as a whole. The length of 

 this vaUey is one hundred and eighty miles, if it is to be considered as extending to St. Jolm's ; 

 but it appears to open into the valley or basin of the St. Lawrence twenty miles to the south. 

 The greatest depression of this valley is between Westport, Burhngton and Port Kent. By 

 sounding close to the edge of the perpendicular rocks about four miles north of Westport, I 

 found the depth to exceed three hundred feet. By soundings at other places in this part of 

 the lake, its depth has been found to be six hundred feet ; it extends therefore five hundred 

 feet at least below the level of the ocean. Situated as the lake is, entirely upon the western 

 side of the valley, its bed must be regarded as a deep chasm principally in the primary rocks ; 

 for from the lake shore upon this side the slope is abrupt along the whole portion where the 

 several mountain ranges reach it, or excepting those portions of it which are bordered by the 

 minor valleys. The character of the slope upon the east side is quite different from the west ; 

 that is, it is longer and much more gradual in its descent ; it comprehends most of the valley. 

 In a direct line, or a line perpendicular to the course of the lake and the Green Mountain 

 range, it cannot exceed twenty-five miles, and probably the average width of this valley is 

 about twenty miles. At many places the lake is bordered by steep banks composed of clay 

 and sand, the greatest height of which is about one hundred feet. It is not my purpose, in 

 this place, to consider the nature of this formation or its age, but it is proper to remark that 

 it is marine, as at many points it furnishes an abundance of fossils belonging to those species 

 which are now inhabitants of the sea on the Atlantic coast ; those too which belong to the 

 same latitudes. Thus, I have found the Mya arenaria, Mya truncata, Natica clausa, Trito- 

 nium anglicum, Tritonium fornicatum, Scalaria groenlandica, Saxicava rugosa, Tcllina gi-oen- 



landica, Balanus miser, Pecten islandicus, Terebratula psittacea, Modiola , and several 



other shells, amounting in all to about twenty species ; all of which, as has been remarked, 

 belong to the present Atlantic shore. We may therefore consider the sediment of this valley 



