CLAY WORKING INDUSTRIES. 219 



make any flint clay plastic, but have failed to prove their assertions or 

 show any basis for their statements. The effect of weather, including 

 frost and heat, will undoubtedly crumble a flint clay to a fine sharp sand, 

 but personal examination of the surface of piles of flint clay which had 

 been exposed for several years failed to show any indication of plasticity. 



Also, the fine dust of flint clays which have been ground dry, which 

 has settled out of the air, has been collected and wet and kneaded with- 

 out any indication of plasticity. 



The composition of the flint clays of the state is illustrated by the 

 following table of analysis: 



