482 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 58. 



length. These prisms only rarely exhibit well-defined prismatic 

 planes and are never terminated in the specimens collected. The 

 fluorite, which is intimately intergrown with the scapolite, is in part 

 rose pink and in part deep purple, the colors varying abruptly. A 

 large specimen of the scapolite was crushed and fluorite free frag- 

 ments carefully selected and ground for analysis. Upon this pov7der 

 the following results were obtained : 



Analysis of scapolite from Trumbull. 



Per cent. 



Si02 51. 38 



AI2O3 25. 22 



FezOj trace. 



CaO 15. 16 



MgO . 73 



MnO trace. 



Na^O 2. 86 



K2O 1.20 



H2O .55 



F 2. 74 



CI 1. 98 



Total 101. 82 



Deduct 0=C1, F. 



Under the microscope the material is transparent and colorless 

 with excellent prismatic cleavage. The indices of refraction as de- 

 termined by immersion are : 



a.=1.55:5±.003 



€=1.540±.003 



w-e= .013 ±.003 



While obviously belonging with the scapolite group this mineral 

 is somewhat unusual in composition. The fluorine content was 

 thought to represent fluorite included in the analyzed powder de- 

 spite precautions. Careful microscopic examination of the powder, 

 however, failed to detect appreciable amounts of fluorite or other 

 extraneous substance. If the fluorine be considered as replacing the 

 chlorine of the marialite molecule, the alkalies become deficient. It 

 seems quite possible that there is here represented a fluorine member 

 of this group, the composition being capable of explanation by as- 

 suming the presence of a fluor-meionite in isomorj^hous mixture. 

 Despite the low soda content the j^resent mineral approaches maria- 

 lite in refractive indices. It resembles marialite also in being un- 

 attacked by boiling concentrated hydrochloric acid. 



