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It is mixed with fluor spar in the thick part of the vein. 



This rare mineral is now proved to occur in this country, and it 

 may interest mineralogists to know that it probably will be found 

 in Boxborough or Bolton in this state, since I have found other ce- 

 rium minerals at those places, associated with the scapolite and 

 petalite at the lime quarries. 



The albite in which the yttrocerite occurs is like that found at 

 the Boxborough lime quarries. 



Dr. J. also read a description and analysis of the pink 

 Scapolite, of Bolton, which is composed of the following 

 ingredients : 



Silicic acid, 45.94 



Alumina, 



Lime, 



Soda, 



Lithia, 



Potash, 



Magnesia, 



Oxide of Cerium, , 



Water, 



99.95 



This mineral occurs in abundance at Whitcomb's lime quarry, 

 near the junction of the white, granular limestone with gneiss rock 

 at the top of the quarry. 



The cavities in the pink scapolite are frequently filled with a 

 yellow powder, which on analysis was found to be a hydrous ce- 

 rium ochre. 



One grain of this substance contains of 



Oxides of Cerium and Lanthanum, . . 0.2 



Yttria, 0.1 



Scapolite, ...... 0.7 



It dissolves readily in muriatic acid and forms a lemon yellow so- 

 lution ; with borax forms easily a transparent glass — orange red 

 while hot, and pale delicate green when cold. 



