10 NEW YORK STATE MUSEUM 
movement of the land is now in progress, the elevation being greater 
toward the north. 
In the succeeding pages evidence will be offered to show that 
most of New York State has been repeatedly covered by ocean water. 
It will also be established that where such mountain ranges as 
the Appalachians, Alps or Himalayas now exist was formerly 
ocean bottom upon which layers of sediment were being spread out. 
Those layers of sediments have been bent, crumpled, folded, and 
greatly elevated above sea level. Thus tt is literally true that the 
great typical mountain ranges of the earth have been born out of 
the ocean. 
Among other important processes of nature which have long been 
active in modifying the earth, are those of weathering and erosion. 
Weathering is brought about by the various atmospheric agencies . 
such as moisture, oxygen, carbonic and other acids, together with 
changes of temperature, and the result is to cause all rock masses 
to disintegrate or decay. In this way most soils are produced, and 
were it not for the process of erosion, soils would be much deeper 
and more widespread than they now are. Weathering prepares the 
material which is carried away by the streams, and this transported 
material is deposited either along the flood plains of the lower 
stream courses or on the bottom of the lake or ocean into which 
the streams flow. Every stream, at time of flood, is heavily 
charged with mud or even coarser sediment which has been derived 
from the wash of the land of its drainage basin. The very presence 
of the sediment in the streams proves that the land is being lowered 
and although, on first thought, it may be supposed that no really 
great change could be accomplished by this means, nevertheless we 
must remember that nature has practically infinite time at her 
disposal so that slowly but surely vast geographic changes are 
wrought and, perchance, a tremendous canyon like that of the 
Colorado in Arizona will be carved out by weathering and erosion. 
The general tendency is for all land masses to wear down to or 
near sea level and, were it not for renewed wuplifts, all land, even 
including mountain ranges, would long ago have been worn down 
to near sea level, that is to the condition of peneplain (almost a 
plain). The former lofty Appalachians were thus worn down to 
the condition of a peneplain which has since been somewhat re- 
juvenated by elevation. Accordingly, that familiar expression “ the 
everlasting hills” is much more exact when made to read “the 
everlastingly changing hills.” 
Still another important process by which the physical features 
of the earth have often been changed is through vulcanism, or 
