THE MINING AND QUARRY INDUSTRY igi2 2$ 



point of fusibility and when applied to clay wares as a slip, produces 

 a rich, brown glaze. Stoneware clays are shipped in a small way 

 from Onondaga county. 



The records for 1912 show that the shipments of crude clay in 

 that year amounted to 8583 short tons valued at $18,980. There 

 were 5 producers engaged in this business. The corresponding total 

 for 191 1 was 14,193 short tons valued at $11,982. The difference 

 in value indicated by the totals is accounted for by the varying pro- 

 portions of the higher priced clays, slip and fire clays, included in 

 the statistics for 1912. 



EMERY 



The emery business, which is confined to a few small operations 

 near Peekskill, has not been very active in the last year or two. 

 The shipments during 191 2, as reported by the companies to whom 

 they were made, amounted to 589 short tons, valued at $6479. ^- n 

 191 1 the shipments were reported as 769 short tons valued at 

 $8810, and in earlier years were still larger, reaching as high as 

 1500 tons at one time. 



The Peekskill emery is a hard, dense rock of rather variable 

 composition and dark gray to black color. It occurs in small lenses, 

 bands and irregular masses in the area of basic igneous rocks that 

 outcrops south and east of Peekskill. The emery bodies are found 

 mainly in the northern section of the area and apparently near the 

 contact of the igneous, or Cortlandt, series with the sedimentary 

 schists. They represent without much doubt segregations within the 

 intrusive mass similar to the titaniferous magnetites that occur 

 within the gabbros and anorthosites of the Adirondacks. The 

 surrounding sediments may have been absorbed more or less into 

 the igneous mass on its way to the surface, thereby contributing 

 some of the aluminum which has crystallized out in the form of 

 corundum and spinel. The intrusion took place after the deposition 

 of the Hudson River strata which are made up largely of argillace- 

 ous materials. 



The emery is a mixture of corundum, spinel and magnetite, with 

 more or less of the silicate minerals that are found in the wall rocks. 

 The proportion of the oxids varies greatly. In some places mag- 

 netite constitutes nearly the whole mass and such bodies have been 

 worked in the past for their iron, though not with much success. 

 Spinel (hercynite) is intimately associated with the magnetite, 

 though its presence is seldom to be established without microscopic 

 examination, being in finely divided particles scarcely distinguishable 



