THE MINING AND QUARRY INDUSTRY 10,12 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. 



Throughout the region there is much similarity in the occurrence 

 of the sand. It is 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 



