42 
GEOLOGY OF THE FIRST DISTRICT. 
when it has accumulated to such a thickness as to buoy up the attached masses of rock and 
earthy materials, it rises to the surface, and transports its load by means of currents or winds 
to distant places. It is ascertained that ground ice forms in water of more than one hundred 
feet in depth. 
No explanation of the formation of this ice, upon scientific principles, has yet been given. 
The following is offered as probable : 
Ice, when rotten in the spring, becomes saturated with water, and then sinks. This proves 
that ice is properly heavier than water, and that its less specific gravity is only due to the 
crystalline arrangement leaving vacuities. Again, in water cooled below the freezing point, 
and then agitated, a portion of the water freezes into minute spiculas, which float in the water 
without rising to the surface ; and if the water be then kept still, they sink, and form a layer 
on the bottom of the vessel. Now the water of rivers and the sea may be similarly affected 
in a degree ; the spiculae forming into masses on the bottom, and cementing the gravel, en¬ 
closing rocks, and finally, by a similar crystalline arrangement, form interstices which render 
the mass of less specific gravity than the surrounding water, and thus rise with rocks and 
gravel adhering. 
Fairhaven falls destroyed on the Poultney river, hy which a part of New-York was thrown 
into Vermont. In one night, one man is said to have set the stream to remove what millions 
could not replace. The fine navigable Fairhaven bay, nine miles in length, was turned into 
flats and shallows where no sloop can enter. The fish were all killed by the feculent flood.* 
Excavating action of Water on Soft Strata. 
It is well known that even the smallest streams excavate deep channels, in soft and de¬ 
structible soils, in a short time. The erosive action of water may be well seen in the rocks 
worn into pot-holes, many feet above the Mohawk river, at Little-Falls ; also at the falls of 
the Hoosick in Rensselaer county, and at numerous other places. These holes, often many 
feet in depth, and shaped like a well, are formed by the water-current keeping a hard pebble 
performing a rotatory or a rolling motion, and thus wearing a deep hole in the rocks. They 
may be found at the falls or in the rapids of almost every large stream, if examined when the 
water is low. 
Alluvial Deposits. 
The effects of a powerful storm of rain at Catskill, on the twenty-sixth of July, 1819, were 
very marked. The rain was so great in quantity, that from fifteen to eighteen inches in depth 
is supposed to have fallen in a short time. From the banks of a small brook which crosses 
the western turnpike, about a quarter of a mile above the north end of Main-street, “ some 
thousands of tons of earth and stones and rock in solid masses were washed out, and borne 
chiefly on to the flats,” or left within the area between the banks.f 
* Geddes, in Sill. Journal, Vol. 11, p.217. f Dwight, in Sill. Journal, Vol. 3, p. 132. 
