26 NEW YORK STATE MUSEUM 



Newfield, Tompkins county ; and one at Syracuse, Onondaga county. 

 The first attempt to use the shales of this State was in 1888 when 

 the Elmira Shale Brick Co., at Elmira, began the manufacture of 

 brick. Some of the undeveloped but still promising sites are found 

 in the central section of the State, such as along the shores of 

 Cayuga lake, north of Ithaca, and in the vicinity of some of the 

 other Finger lakes, where the shales are so situated that they can 

 be readily investigated and cheaply worked, and also in Erie county, 

 a section that is well supplied with cheap fuel, has both water and 

 rail transportation and is close to the important markets. 



Methods of manufacture. There are three kinds of material 

 used in the manufacture of paving brick : fire clays, soft plastic 

 clays, and shales. The fire clays generally give a product of light 

 brown or yellow color, the plastic clays and shales a dark brown or 

 red color. The industry in this State makes use only of the soft 

 plastic clays and shales. 



The crude materials are mined chiefly with the pick and shovel, 

 though several companies are using steam shovels for loading. In 

 most cases the plant has been placed fairly close to the open cut so 

 that the material can be sent to the crushers by gravity without the 

 necessity of a long haul. In two plants, however, there are hauls 

 respectively of one and ten miles by rail. Hand sorting has to be 

 resorted to at several localities in order to remove the thin layers of 

 coarse-grained sandstone and limestone. 



In nearly all cases the material receives a preliminary crushing 

 in jaw or gyratory crushers before it is sent to the dry pan. It is 

 reduced in the dry pan to a size that will pass a 3-16 inch mesh, 

 then screened and the oversize returned to the pan for further grind- 

 ing. The pulverized material then goes to the storage bins. The 

 dry pan consists of a revolving slotted or perforated iron plate hav- 

 ing a rim about one foot in height around the side. Two heavy 

 iron mullers resting on edge, revolving by friction against the bot- 

 tom plate, crush the material. 



From the storage bins the pulverized material goes to the pug 

 mill where the necessary water is added to form a stiff mud. The 

 pug mill consists of a semicylindrical, horizontal trough of metal 

 through the center of which revolves a shaft, furnished with steel 

 arms, so set as to mix thoroughly the dry material and water and to 

 feed it continually forward to the brick machine. 



The brick machine, generally known as the auger machine, con- 

 sists of a heavy tapering steel barrel set directly under the pug mill 



