CLAYS OF KEW YORK 853 



domestic use for scouririg steel utensils is simply a fine-grained sili- 

 cious clay, wliich is deposited during high tide along the banks of 

 the Parrot river in England. 



Road materials 



Clay or shale is used in the construction of wagon, roads and 

 railroads. 



Wagon roads. Soft plastic clay when, used by itself is a very poor 

 road material, for the reason that in wet weather it makes the road 

 almost impassable at times, and in dry weather it is exceedingly 

 dusty. 



Shales if soft and very argillaceous are almost as bad, but, if the 

 shale is silicious and well cemented by iron, it often makes a 

 splendid road, specially if the trafiic is not very heavy. In many 

 portions of IsTew York state, shale is used to a large extent with good 

 results. In some regions the shale has been partly changed to 

 slate, owing to the folding which the rocks have been subjected to 

 subsequent to their formation, and the value of the shale for road 

 metal is then increased. 



Railroads. In many portions of the west where rock is hard to 

 obtain for railroad ballast, clay is used in a very ingenious way. 

 The material is dug up along some railroad siding where a bed of it 

 has been found, and piled in long heaps interbedded with old rail- 

 road ties. This mass of ties is then set on fire at the bottom of the 

 heap, and the mass of clay is gradually baked from bottom to top, 

 the result being a mass of burned clay lumps of the right size for 

 putting on the road bed and as hard as almost any ordinary stone 

 that could be used for the same purpose. While this is an import- 

 ant use of clay, it. would find no application in the east where 

 stone for railroad ballasting is so i^lentiful. 



For a detailed description of this application of clay, see Min. 

 incl. vol. 6. p^^^j^ 



Puddle is a mixture of clay and gravel often used in engineering 

 construction. The clay employed must be such that it will bind 

 the pebbles firmly but not crack in drying. The best results would 

 therefor be yielded by a plastic clay containing an abundance of 

 fine sand. 



