THE MINING AND QUARRY INDUSTRY IQII 13 



They are commonly of blue color, weathering to yellow at the sur- 

 face, and contain rather high percentages of iron and fluxing 

 ingredients. Extensive deposits occur in the Hudson and Cham- 

 plain valleys where they form terraces at different elevations, from 

 near water level to several hundred feet above, and also in some 

 of the large valleys in the interior of the State. These clays gen- 

 erally burn at a relatively low temperature to a red color. 



Deposits of white-burning and refractory clays are restricted to 

 Long Island and Staten Island. They belong to the Cretaceous, and 

 occur as scattered, but in some places heavy, beds. They are 

 adapted for fire brick, stoneware, terra cotta and the better grades 

 of building brick. 



The single example of any considerable accumulation of residual 

 kaolin that has come to notice is found near Shenandoah, Dutchess 

 county. The property known as Fowler's kaolin mine has produced 

 small amounts of white but rather quartzose material which has 

 found use as stove cement. It appears to be a disintegration 

 product of pegmatite formed in place and by some chance has 

 escaped the general erosion. 



The use of shale which is abundant in many of the stratified rock 

 formations has been of increasing importance of late years. The 

 principal beds are found in the Devonic, Hamilton, Portage and 

 Chemung groups. They are worked mainly in the western counties 

 for the manufacture of paving brick, tile and pressed building 

 brick. 



PRODUCTION OF CLAY MATERIALS 



Details of the production of clay materials in New York State 

 during the last two or three years are given in the accompanying 

 tables which are based on reports from practically every producer 

 in the several branches of the industry. 



The general condition of the industry during 191 1 can hardly be 

 described as prosperous. Building operations in most of the larger 

 cities were on a scale below the average of recent years and con- 

 sequently the market for clay structural materials showed little 

 activity. The Hudson river brick industry made relatively the 

 poorest record of any branch, owing to the fact that the yards had 

 to carry over a very heavy stock from the previous year ; on the 

 other hand it benefited by a slight increase of the prices in the New 

 York market. The pottery trade fared better than most lines, and 

 the production was well maintained. 



The output of clay materials of all kinds in 191 1 was valued at 

 $9,751,659. Compared with the total for the preceding year, which 



