Erythrite : Stilpxomelane var. Chalcodite, Etc. 195 



good crystal of this rare and interesting species which, in its massive 

 form, had been recorded in the Annual Report of the Geological Survey 

 for the year 1886.* An analysis was also published by the late Dr. F. A 

 Genth in 1889 t 



The crystal to which I now refer measures about 12x8 mm., is 

 flattened parallel to the orthopinacoid, as is often the case in monazite, 

 and is of a clove-brown to reddish-brown color with a decidedly resinous 

 lustre on fractured surfaces. A blowpipe examination and qualitative 

 tests shewed its general composition to be that of monazite. 



The faces of the crystal are too rough to admit of precise measure- 

 ments, but the following planes were determined with a tolerable degree 

 of accuracy: 



00 P55 , 00 PicT, ooP3,coP2, Poo", PSr. 



The crystal was isolated, imbedded in albite, and was readily 

 broken out from its matrix. 



Apatite. 



It is a fact not generally known amongst mineralogists that at many 

 of the phosphate mines along the Du Lievre River, Quebec, beautiful 

 translucent to transparent specimens of apatite are to be found which 

 possess the property of pleochroism in a most marked degree. 

 In an almost transparent cleavage piece measuring 13x15 mm. 

 which now lies before me, the color, viewed in the direction of the 

 principal axis of the crystal, is a bluish-green, whilst in a direction at 

 right angles to this it is a rich oily green, the contrast being most marked. 



Little cubes h in. and more in diameter have been cut from similar 

 cleavages and serve to illustrate pleochroism, for teaching purposes, to 

 perfection. The only mention of similar crystals from a North American 

 locality which has come under my notice is a short note by Mr. Geo. 

 F. Kunz J on a fragment of an apatite crystal from near Yonkers in the 

 State of New York. 



*Ann, Rep. Geol. Surv. Can. (886, Part T. p. 11. 

 tAm. Jour. Sci., Vol. XXXVIII, p. 203, 1889. 

 % Am. Jour Sci., Vol. XXXVI, p. 223, 1888. 



