of Boston and its Ticinity, 163 



The fragments are imperfectly tabular, and indeterminately 

 angular, and sharp edged. 



It phosphoresces with a brilliant green light, when projected 

 in powder on a heated iron. 



The speciiick gravity is from 2.10 to S.fiO. 



Chymical Characters, 



Before the blowpipe it fuses, with ebullition into a white 

 enamel filled with bubbles. The amorphous, when placed in 

 nitrick acid, feebly effervesces and falls partially into grains. 



Geological 'Situation and Locality. 



It occurs massive and disseminated in a bed of Carbonate of 

 Lime in Micaceous Schistus, at Ctielmsford, Its accompanying 

 minerals are Quartz, black Mica, and Phosphate of Lime, 



Me marks. 



f 



Schaalstone we have never seen ; it is a very rare mineral and 

 has only two known localities. The above mineral bears a greater 

 resemblance to Schaalstone, as described by systematick writers, 

 than to any other fossil ; but, there are also considerable differ- 

 ences. Schaalstone is said to be phosphorescent merely by the 



friction of steel point ; the mineral above described exhibits 

 no such property, but it is brilliantly phosphorick, when plac- 

 ed on a heated iron; this may be the case with Schaalstone, 

 but it is not mentioned by any author we have seen. Its fusibil- 

 ity, and its very imperfect tabular structure, likewise distinguish 



S3 



