154 NEW YORK STATE MUSEUM 



$15,875 respectively the value of paving blocks and building mate- 

 rial. The total quantity of crushed stone in 1905 was 774,111 

 cubic yards and in the preceding year 610,285 cubic yards. The 

 greater part of the crushed stone was sold for road material, though 

 the quantities thus used can not be accurately stated. The paving 

 blocks and building stone were quarried on Staten Island. There 

 were seven companies in 1905 that reported an output. 



Bibliography 



Dickinson, H. T. Quarries of Bluestone and other Sandstones in New York. 



N. Y. State Mus. Bui. 61. 1903. 

 Eckel, E. C. The Quarry Industry of Southeastern New York. N. Y. State 



Geol. 20th An. Rep't. 1902. 

 Hall, James. Report on Building Stone. N. Y. State Mus. 39th An. Rep't. 



1886. 



Geology of New York: Report on Fourth District. 1843. 



Mather, W. W. Geology of New York: Report on First District. 1842. ' 

 Merrill, F. J. H. Mineral Resources of New York. N. Y. State Mus. Bui. 15. 



1895. 

 Smock, J. C. Building Stone in the State of New York. N. Y. State Mus. 

 Bui. 3.. 1888. 



Building Stone in New York. N. Y. State Mus. Bui. 10. 1890. 



Vanuxem, Lardner. Geology of New York : Report on Third District. 1843. 



TALC 



The industry based on the mining and preparation of talc is car- 

 ried on in St Lawrence county, where there are large deposits of 

 foliated and fibrous talc adapted for paper manufacturing and other 

 uses. The deposits occur in a belt of crystalline limestone that is 

 interfolded with, and surrounded by, Adirondack gneiss. The 

 limestone is part of a series of related rocks that are extensively 

 developed on this side of the Adirondacks. It differs, however, 

 from the usual type in having a finer texture and in the more abund- 

 ant inclusions of silicates, specially tremolite and pyroxene. 



The geology of the talc deposits has been studied by C. H. 

 Smyth jr, who has shown that they are the result of chemical altera- 

 tion of the silicates in the limestone. The method of derivation 

 is described by Dr Smyth as follows : 



The tremolite schist represents portions of the limestone forma- 

 tion which contained a large amount of silicious sediment. Meta- 

 morphism produced crystallization of the mingled calcareous, 

 magnesian and silicious materials, forming tremolite. Where the 

 calcareous material was in considerable quantity there was formed 

 a tremolite limestone; where it was a minor constituent there was 

 formed a tremolite schist. Under the influence of subterranean 

 waters chemical changes have been produced. The tremolite has 

 taken up the elements of water, the lime has passed away into solu- 

 tion, and talc has resulted. 



