200 M. E. WADSWORTH 



The term Zirkelite was again used in the same way in my 

 Report of the Geological Survey of Michigan for 1 891-2 (1893, pp. 

 90, 97, 138, etc.). 



It was also published in my classification of rocks given in 

 the Catalogue of the Michiga?i College of Mines (Michigan Mining 

 School), 1891-2, p. 104; 1892-1894, Table XI; 1894-1896, 

 Table XI. 



Further the term Zirkelite is defined in accordance with my 



usage in Lewinson-Lessing's Petrographisches Lexikon, 1893, p. 



252) ; and accounts of it are given in the Neues Jahrbuch fur 



Mineralogie, 1893, II, p. 292, and in Kemp's Handbook of Rocks, 



1896, p. 170. 



M. E. Wadsworth. 



Michigan College of Mines, Houghton, Mich., 

 December 17, 1897. 



[The prior use of the name Zirkelite is certainly established, but it is a 

 question how far a petrographer is justified in stigmatizing the name of a 

 fellow worker by attaching it to an indefinitely decomposed and ill-defined 

 rock.— J. P. I.] 



