MINERAL RESOURCES OF THE STATE OF NEW YORK 237 



with the conditions of use. The testing of sands has become an 

 important function of engineering laboratories, with the growing 

 recognition of the need for certain standards, just as in reference 

 to other uses of the material. The consequence is that the 

 available supplies of high-grade sands are nowhere so extensive as 

 might be surmised from the wide presence of sand deposits and in 

 some considerable areas they are practically absent. In the last 

 few years there has taken place a marked change in the productive 

 industry by reason of the centralization of operations in certain 

 localities where the best materials are found; much of the product 

 now undergoes preparation by washing or screening which necessi- 

 tates mechanical installations and lends a permanency to the 

 enterprises which they formerly lacked. 



The largest market for building sands in the State is New York 

 City. More than one-half of the quantity and value of the annual 

 product is probably used in the metropolitan district. The supply 

 is obtained from different sources, mainly on tidewater, of which 

 the more important are on the north shore of Long island, principally 

 in Nassau county. The sands are obtained from the beaches and 

 from the beds which are exposed in the series of bluffs that front 

 the beaches, showing a vertical section of sands, gravels and bowlders 

 of 100 feet or more. The beaches represent the resorted materials 

 of these beds which are of Pleistocene age and partly of marine 

 and partly of m.orainal character. The beach sand is obtained by 

 dredging and is sufficiently clean and sized to be marketable as it 

 comes. The sand from, the beds is excavated by steam shovels 

 working against the face of the bank and is mostly prepared in 

 washers which afford different sizes ranging from gravel to fine 

 sand. Barges are used for transporting the sand which is used in 

 building and construction work in New York and vicinity. The 

 larger plants are those of the Goodwin-Gallagher Sand and Gravel 

 Corporation at Port Washington and Northport, Phoenix Sand and 

 Gravel Co., Roslyn, and O'Brien Brothers, Inc., Hempstead. Special 

 grades of sand that are obtained here include fire and core sand, 

 engine sand and filter sand. 



In the Hudson valley, north of the Highlands, a series of terraced 

 beds com,posed of clay, sand and gravel rise from the water's edge 

 to levels that gradually increase to the north. The clays were 

 deposited in standing water, but the coarser materials have the 

 appearance of marginal moraines laid down while the ice was in 

 retreat. Some of the deposits consist of ill-sorted materials which 

 were melted out of the glacier and others are water-washed and 



