MINERAL RESOURCES OF THE STATE OF NEW YORK 



53 



transverse stream valleys and along the shores of the Finger Lakes 

 which occupy deep trenches in the Devonian rocks. The shales 

 show a considerable range of composition, some being very siliceous 

 with relatively small porportions of clay substance, and others are 

 normal clay shales. Their utility is a matter for local investigation 

 of conditions and practical tests. In many places they have been 

 found to make an excellent paving brick, quite as good as the material 

 made from fire-clays of Pennsylvania, Ohio and Michigan. Among 

 the localities where the shales have been used for brick are Angola 

 and Jewettville, Erie county; Jamestown, Chautauqua county; 

 Olean, Cattaraugus county; Alfred center, Allegany coiinty; Coming 

 and Homell, Steuben county; Newfield, Tompkins county; Bing- 

 hampton, Broome county; and Catskill, Greene county. 



The Hudson River shales which outcrop along the Hudson above 

 the Highlands are usually hardened slaty materials developing 

 little natural plasticity when ground. Some phases are high in 

 silica, while the lime and iron content may be high. They have 

 not been employed in brick manufacture, although the more argil- 

 laceous types which occur here and there might serve in mixture 

 with the plastic local clays for the purpose. 



The Salina, Clinton and Medina formations contain much shale, 

 but in general it is not of a commercial grade. 



The physical properties of the Devonian shales with reference 

 to their adaptability to brick manufacture have been studied by 

 Prof. H. Ries.^ The following analyses of shale samples from 

 different localities of the State will indicate their general chemical 

 nature. 



SiOz 



AI2O3 



FejOj 



CaO 



MgO 



K2O 



NaaO 



CO2 



H2O 



Total . 



•30 

 •85 

 ■55 

 •36 

 •49 

 ■65 

 •35 

 .04 



•30 



57^79 



16.15 



5.20 



2^73 

 4.67 

 4. II 

 1 .22 

 3^42 

 450 



64 



45 



17 



77 



7 



04 





5« 



I 



H5 



2 



52 



I 



95 







53-20 



23 25 



10.90 



1 .01 



.62 



2 .69 



6.39 



65 



15 



15 



29 



6 



16 



3 



50 



I 



57 



5 



71 





58.44 



64.30 



27-45 



33-60 



1. 16 



1.46 



2.23 



1.30 



99.89 



99-79 



099.90 



a Tctal also includes sulphuric acid, .41; titanic oxide, .91: manganese oxide, .52. 



1 Physical Tests of the Devonian Shales of New York. N. Y. State Mus., 49th 

 Ann, Rep't, v. 2, 1895. 



