694 



Report of the State Geologist. 



of this mixture were tested with the following results. The moderately 

 plastic paste shrank four per cent, in drying, and nine per cent, in burning. 

 Air dried briquettes had an average tensile strength of ninety-seven pounds 

 per square inch, and a maximum of one hundred pounds per square inch. 



Incipient fusion occurred at 1,900° F., vitrification at 2,050° and 

 viscosity at 2,150° F. 



The mixture of clay and shale is ground in dry-pans and then passes to 

 the pug mill on the floor above, whence, after tempering, it is discharged to 

 the auger side-cut machine. The bricks are repressed, dried in tunnels, and 

 burned in down-draught kilns. The company has recently erected a large 

 continuous kiln ; in this kiln, most of the firing is done in temporary fire- 

 places built in the doorways of the kiln, no grate bars being used ; it is 

 claimed that practically no fuel is charged through the small openings in the 

 roof of the kiln. 



Portage. (See Geology of the Fourth District of New York, p. 224). 

 Another important shale occurs in this member of the Devonian formation. 

 The group consists of a lower shaly member, the Cashaqua shale, a middle 

 member of shales and sandstones, and an upper one of sandstones. 



The Cashaqua shale is exposed along Cashaqua creek where it is a soft 

 green shale that weathers to a tough clay. It also occurs along Seneca lake 

 and at Penn Yan, but east of this becomes very sandy. 



Good exposures are seen along Allen's creek and Tonawanda creek, and 

 the branches of Seneca and Cayuga creeks. On lake Erie at Eighteen-mile 

 creek it is thirty-three feet thick, while along the Genesee river it is 150 feet 

 thick. 



Concerning the Gardeau shales, Professor Hall states that they are 

 exposed along the Genesee river where the section involves alternating layers 

 of shales and sandstones. Toward the east the sandstones become more 

 prominent, but to the west, the shales increase and predominate so that along 

 lake Erie, "the Cashaqua shale is succeeded by a thick mass of black shale, 

 and this again by alternations of green and black shales " which aggregate 

 several hundred feet in thickness. 



Angola, fcri< county. The Portage shale is used by J. Lythe <fc Sons at 

 this locality for the manufacture of sewer pipe, fire-proofing, drain-tile, and 

 terra-cotta. The clay is somewhat less gritty than that at Jamestown. It is 

 a greyish, moderately coarse grained shale and contains scattered streaks of 

 bituminous matter. 



