58 NEW YORK STATE MUSEUM 
The sand and gravel beds of the State are mainly of glacial 
origin, as the whole territory within the limits of New York, in 
common with the northern section of the United States east of the 
Rocky mountains, was invaded by the Pleistocene ice sheet which 
removed all the loose material accumulated by previous weathering 
and erosion, and left in its retreat a mantle of transported boulders, 
gravels, sands and clays. In places these accumulations have the 
character of unmodified drift or morainal accumulations in which 
the materials are more or less intermixed, and are then of little 
industrial value. But more generally the deposits show a sorted 
stratiform arrangement due to having been worked over by the 
glacial streams and lakes. Such is the condition in many of the 
larger valleys like those of the Hudson, Champlain and Genesee 
where sands, gravels and clays occur separately in terraced beds 
extending far above the present water level. Later water action 
may have effected a beneficial re-sorting of the materials as in- 
stanced by the beach sands of Long Island and some of the lakes 
in the interior of the State. / 
A measure of the importance of the sand and gravel in- 
dustry may be had from the accompanying table which, however, 
lacks something in the way of completeness and accuracy. The 
figures relating to the molding sand production are believed to be 
a close approximation to the actual totals, but those for building 
sand and gravel may vary considerably from the true quantities, 
perhaps understating them by as much as 25 per cent. The build- 
ing sand operations are so widely scattered and in many sections 
carried on in such haphazard or fugitive manner that it is extremely 
difficult to cover them all in a statistical canvass. 
Production of sand and gravel 
MATERIAL 1910 IQII = ® 1072 
IMI@NGhIOeS Saal, 052 ¢enano coos ceo woes $424 O15 $420 780 $422 148 
Cites, Qin! MRS SEVAG!, oppo acanccsceac 33 709 27 484 55 910 
IB\uIGhbMS? SAH! oo cana cadeecsdovccce I O16 598 b 750 000 I 156 002 
Other samcdyaies nein ee ee eae ee 65 835 b 50 000 b 75 000 
Graveliicn eh aa ne ee 589 551 479 103 840 669 
Totals 2g aepcte ye ene ee Ri) 112X0) O's) || Siu 72a B07 $2 549 729 
a Includes glass sand, filter sand, engine and polishing sand. 
b Partly estimated. 
