THE MINING AND QUARRY INDUSTRY IQ12 59 
Molding sand. The business connected with the locating, dig- 
ging, grading and shipment to market of molding sands involves a 
degree of skill and experience on the part of the operator that 
makes it a rather specialized branch of the industry. Sands pos- 
sessing the requisite qualities for employment in the molding of 
metals are also rather restricted in distribution. The business, 
therefore, has elements of stability and permanency not shared to 
any extent by most of the other branches. 
The main output of molding sands in New York comes from 
the middle Hudson valley. The deposits that are actively worked 
extend along both sides of the river from Washington and Saratoga 
counties on the north to Orange and Dutchess counties on the 
south. The product is often spoken of as “Albany ” molding sand, 
probably owing to the fact that Albany is near the center of the 
district. Albany county furnishes a large part of the output, most 
of which is dug in the southern townships of Bethlehem and Coey- 
mans. 
Thréughout the region there is much similarity in the occurrence 
of the sand. It 1s always found directly below the soil, and where 
this is lacking, as in the sand dune tracts of Albany and Schenec- 
tady counties, the sand is also absent. The thickness of the soil 
cover, which has the character usually of a sandy loam, well 
sodded, averages about one foot. There is no sharp division be- 
tween soil and molding sand, the change being manifested by a 
gradual decrease of plant fibers and carbonaceous matter as the 
valuable layer is reached. The underlying material consists of sand 
that is sometimes difficult to differentiate from the molding sand 
itself. As a matter of fact, there are no fixed standards determin- 
ing the selection, and there is considerable variation in the physical 
qualities of the sands shipped by the different producers. The 
most valuable grades consist of the very fine sands which can be 
used for brass and stove castings ; they are consequently most sought 
for and may be exploited exclusively even when accompanied by 
coarser kinds that have a more limited sale. 
The most notable feature of the distribution geologically is that 
the sands occupy the site of the glacial Lake Albany. This lake, 
formed in late Pleistocene time, reached well up the slopes of the 
middle Hudson valley and the confluent branches and was fed by 
the flood waters resulting from the melting of the ice sheet in its 
northward retreat. These waters washed down the rock-waste of 
clays, sands and gravels made by the erosion of the ice and brought 
