144 NEW YORK STATE MUSEUM 



On Long Island for example the clay is found almost entirely 

 along the north shore ; it no doubt underlies most of the island, 

 but on the southern side there is m most instances such a cover- 

 ing of sand as to make it useless. The presence of clay can often 

 be detected in railroad cuttings, in the sides of gullies or ravines. 

 In many instances however the occurrence of clay is only sus- 

 pected, and then borings must be made with an auger to 

 determine its presence. As a deposit of clay is seldom of uni 

 form thickness throughout its extent, a sufficient number of 

 borings should be made in order to fully determine this point ; 

 a bed of clay may be 40 feet deep at one point and thin out to 

 five or six feet within a distance of 15. The writer has seen 

 several instances in which expensive plants have been erected 

 and come to a speedy end simply because the clay gave out, 

 whereas the disaster might have been avoided by previous 

 exploitation. Another important point to determine is the 

 presence of sand for molding and tempering. Many of the clays in 

 this state can not be made into brick without the addition of sand. 

 Along the Hudson Eiver and on Long Island tempering sand is a 

 much needed article, but fortunately it is near at hand. With 

 molding sand it is different, for wherever soft mud machines are 

 used it is necessary. Yery often it can be obtained from some 

 neighboring hiU, but sometimes it has to be brought long 

 distances. 



The presence of a large deposit of clay is not the only fact 

 necessary to be determined. The question next arises, is the 

 material available for the purpose for which it is to be used, and 

 what sort of machinery will be the best suited to work it. By 

 far the best way is to take several barrels of clay and have it made 

 into the desired product by different methods. There are brick- 

 yairds where this can be done, or even the manufacturers of dif- 

 ferent machines offer to do this at their works. Crushing a lump 

 of clay between the fingers or tasting it will give some idea of 

 grittiness, but it is impossible to tell by this method the quality 

 of the clay or its availability for one purpose or another. 



Having determined by boring or otherwise the extent and 

 thickness of the clay at the locality where the brickyard is to 



