Cyanite from a New Locality. 



199 



substance; along cleavage directions in the cyanite; and occa- 

 sionally along irregular fractures, but in the latter case the 

 fracture in the cyanite sometimes passes through the larger 

 grains of rutile, indicating that the rutile formed prior to the 

 fracturing of the cyanite. The relations of the rutile to the 

 cyanite and quartz are such as to preclude its formation subse- 

 quent to that of the associated minerals, cyanite and quartz 



Fig. 3. 



Fig. 3. Photomicrograph of cyanite altered to muscovite folia. Inclu- 

 sions of rutile crystals are shown. Magnified 105 diameters. 



(figs. 2 and 3). Figure 3 is a micro photograph showing 

 rutile inclosed in secondary muscovite derived from the altera- 

 tion of cyanite, without change of the rutile in the original 

 mineral cyanite. 



Cyanite. 



Cyanite, in the schist described above, ranges in amount 

 from a predominant to a very subordinate constituent, in size 



