The Monoclinic Pyroxenes of New York State. 



135 



Pyramids. Terminated crystals as a rule show the positive and 

 negative unit pyramids and the positive pyramid o ( 221). The 

 latter is rarely present without the other two. The pyramid 

 V (221) is rare and usually small when present. A notable excep- 

 tion to this is the white augite found in the dolomitic limestones 

 of Dutchess, Westchester and New York Counties. The iJ(311) 

 has onl}^ been observed on crystals from two localities, viz., Rus- 

 sell and De Kalb and the pj-ramid /i ( 331) is even rarer and found 

 on crystals from Diana, Lewis Co., .a (121) and a (312) have onl}' 

 been noted on augite of Orange Co. 



A curious inequality of development is shown by the diopsides 

 of DeKalb.on which one face of it (111) is often large, while the 

 other is so small as to appear absent. 



The pyramid faces are often dull or even slightly rough, and 

 seamed with a series of longitudinal pits. 



The accompanying table gives the distribution of the different 

 faces found on the New York pj'roxenes. 



TABLE GIVING OCCUREENCE OF CRYSTAL FORMS AT THE DIF- 

 FERENT LOCALITIES. 



Locality. 



Adams' Lake 



Cheever 



Chilson Hill 



DeKalb 



Diana 



Gouverneur 



Greenwood Lake 



Hammondville 



Highlands of Hudson. 



Kingsbridge 



Macomb 



Monroe Township. . . . 



Natural Bridge 



Oxbow 



Pawling 



Pierpont 



Pitcairn 



Port Henry 



Rossie 



Russell 



Sing Sing 



Tilly Foster 



Warwick 



a 



c 



b 



m 



/ 



e 



z 



u 



s 



V 







A 



A 



P 



/« 



a 



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