48 NEW YORK STATE MUSEUM 



Some are of morainal character and were laid down under the ice or 

 at the ice front. They consist of stiff clays in ill-sorted layers 

 mingled with sands, or of bowlder till made up of hard blue clay in 

 which lie all sorts and shapes of pebbles and bowlders that have been 

 groimd and polished by abrasion as they were swept along by the 

 ice. Deposits of this character have not been utilized to any extent 

 except in one or two localities, owing to the difficulties presented by 

 the working of the mixture of clay and rock. 



Most of the clay beds that are exploited for brick-making are the 

 result primarily of glacial action but sorted and deposited by water; 

 they represent the rock flour and fine materials carried along with 

 the moving ice until swept out by the subglacial streams to be finally 

 deposited in some quiet water, perhaps at a long distance from the 

 ice itself. Such beds are found in many valley bottoms in basin- 

 shaped areas which are the sites of lakes and ponds formed tempor- 

 arily by obstructions of ice or moraines. They are also formed in 

 places as terraced beds along the valley that reach well above the 

 present valley floor. In thickness they range from a few feet up to 

 100 feet or more. Their color normally is blue, but in the upper beds 

 exposed to the weather they may be yellow from oxidation of the 

 iron. Beds of fine sand are frequently interstratified with them, the 

 alteration of the two materials taking place with marked regularity 

 suggestive of a periodical change of the conditions of deposit. The 

 Hudson and Champlain valleys were flooded to a great depth in 

 late Pleistocene, so that deposits of clay occur in terraces that extend 

 from the present water levels to several hundred feet above. 



Long Island. Clay beds outcrop along the north shore and at 

 several points on the main line of the Long Island railroad. The 

 common brick clays of Pleistocene age extend in patches almost the 

 entire length of the island. They are generally intermixed with 

 gravel and bowlders, so that sorting and crushing are necessary 

 before used in brick machines. The deposits do not reach any great 

 thickness and have to be worked in pits rather than banks. The 

 depth of the pits is usually 10 or 12 feet. The Cretaceous clays are 

 somewhat sandy in character. Some are adapted for stoneware and 

 the coarser pottery. The more sandy beds require very little prep- 

 aration for brick making, and in some yards are used without the 

 addition of sand. Elm point, near Great Neck, has been a source of 

 stoneware clay. Other deposits of Cretaceous clays are found on 

 the east shore of Hempstead harbor, at Glen Cove, on Center island 

 in Oyster bay, on Little Neck in Northport bay and other localities. 

 Brick yards have been operated at Garden Citj'-, East Williston, 



