no NEW YORK STATE MUSEUM 



irregular, although originally the sands were deposited on a level 

 platform. 



Another influence of the same agency is to be found in the even- 

 ness of texture which characterizes the sand ; the first sorting by 

 the water may have produced a fairly even grain, but no doubt this 

 feature has been further promoted by the sifting action of the wind. 

 The uniformity of texture does not obtain over long distances, but 

 only within rather narrow limits, as the same layer may be seen to 

 change gradually to a coarser or finer condition when traced along 

 the surface. Some banks of a few acres extent may produce two 

 or three commercial sizes. The coarsest grain seldom approaches 

 that of fine gravel, the latter material being rarely met with 

 among the molding sands. 



The drift sand from the bare wind-swept areas has the same 

 textures as the sand that lies under sod, but differs from the latter 

 markedly in appearance and in other features. It is an incoherent 

 aggregate running readily on slopes under slight propulsion, and 

 has no strength, to speak of, when moistened. Its color is grayish 

 from the admixture of dark grains of shale and sandstone with 

 those of white or transparent quartz. On the other hand, the sand 

 taken from under an old soil has a brownish yellow or ochreous 

 color and contains enough clay usually to show good bonding 

 power. Banks of the latter will stand vertical for a long time 

 unless thoroughly dried out by removal of the protecting cover. 

 This yellow, loamy sand in depth usually grades over into a sand 

 of looser more " open " nature which resembles more or less the 

 drift sand. 



It is rather evident from the associations that these variations 

 reflect different stages of weathering and decomposition after the 

 sand was deposited. Wherever the sand has been held down by 

 soil for a long period the shaly particles have disintegrated so as 

 to form clay and at the same time some of the iron has been released 

 and oxidized. The change has proceeded from the surface down- 

 ward under the influence of moisture, frost and probably the acids 

 of the soil. 



The Molding Sand Layer 



The molding sand represents a very small fraction of the whole 

 accumulation of sand. Its occurrence is quite without rule, except 

 that when present it is always the layer directly below the soil. In 

 many places this layer may lack the necessary qualities of texture 

 or cohesiveness to constitute a good sand, and there is no way of 

 determining the conditions except by actual exploratory tests. 



