148 
GEOLOGY OF THE FIRST DISTRICT. 
are washed away; and the operation is repeated whenever the base of the cliff is not suffi¬ 
ciently supported, and valleys are formed, continually penetrating farther inland along the 
course of the spring. In these little valleys, the springs wash away a part of the materials, 
and then more slide down (Vide the wood-cuts on land-slides in this volume, p. 33). 
Valleys are widened by the same cause, in places too numerous to mention, in the clay 
formation of the Hudson valley. Faults of these beds are also thus produced (Vide Plate 
31, figures 5 and 8). Wrinkling of the strata is also produced by the same cause, by the 
lateral forces tending to crush and separate the laminas, and force them between the yielding 
saponaceous layers (Vide Plate 31, figures 2, 4, 5, 6, 7). 
(/). Direction and strength of currents that deposited the quaternary division, and the 
condition of this part of the earth's surface at this period. 
The subject of the direction of the currents, as indicated by the lamince and water lines 
of deposition, has not been studied with the care it deserves, and no result is offered as 
obtained by careful induction from many facts ; but the general course of transport is from 
the northward. It is believed that when this subject shall have been attentively studied, the 
directions will be found to be such as would be produced by a general current setting from 
the north through the valleys that will be named,* modified by tidal currents, and the various 
irregularities of the forms of the hills, mountains and other obstacles that must, when covered 
partly or entirely with water, have produced eddy currents in various directions, and deposi¬ 
tions varying greatly in their quantities and degrees of fineness. 
It is evident from the localities in which the quaternary deposits are situated, that the gene¬ 
ral contour of the country was, in the main, the same as at present; and that the change of 
level necessary to bring these formations above the water level, has been in mass, without 
much relative change of position. 
The larger sand and gravel deposits, as the superior members of the quaternary, have been 
deposited at the confluence of great valleys, through which we may suppose currents to have 
flowed, and consequent eddies to have been formed, in which matter held in suspension would 
be precipitated. 
EXAMPLES. 
1. The Saratoga plains, are at the junction of the upper Hudson valley from the west, and the Cham¬ 
plain valley from the north. 
2. The Albany and Schenectady sand plains, are at the junction of the Mohawk and Norman’s kill val¬ 
leys, with the Hudson valley. 
3. The Kingston plains, are at the junction of the Esopus creek and Mamakating valley from the south¬ 
west, with the Hudson valley. 
See page 150. 
