600 fenner: babingtonite from passaic counts 



summary of the evidence which has come to view in its bearing 

 upon the question of the identity of the original mineral or 

 minerals of the cavities. Accordingly several days have been 

 devoted to visits to the New Jersey localities where the minerals 

 and casts have been found and to the collection of material for 

 examination. Considerable new evidence has been brought to 

 light and will be presented here. 



One of the chief points upon which information was considered 

 desirable was the question of the relative importance and abund- 

 ance of the two minerals babingtonite and anhydrite. It was 

 found that the quantity of anhydrite so far discovered was very 

 small and that no new material had been opened up since that 

 which Mr. Allen described. However, through the kindness of 

 Mr. Allen and of another collector, Mr. Lovell, of Paterson, the 

 opportunity was given to examine several specimens. The 

 anhydrite occurs in large crystals in a quartz matrix and there 

 seems to be no reason to doubt that it is of primary origin and 

 does not simply fill cavities left by the removal of some other 

 substance. In the specimens seen it occurs either in simple 

 crystals of nearly square section or in slightly radiating or fan- 

 like crystals produced by a spreading-out in the direction of one 

 of the axes. Careful examination failed to show any indication 

 of laminae of quartz projecting from the walls into the anhydrite. 

 On the contrary the walls of the matrix appeared to be perfectly 

 straight and smooth and differed in that respect from those of 

 most of the rectangular casts. However, it does not seem 

 unlikely that under certain conditions of decomposition and re- 

 moval of the anhydrite such laminae might be built up along the 

 cleavage planes. The evidence appears quite clear that anhy- 

 drite was the original mineral of some of the rectangular cavities, 

 but the later investigation has strengthened the belief that 

 babingtonite also was an abundant and important mineral and 

 that certain of the casts left by its crystals are of such size and 

 form that they present a remarkable resemblance to those due 

 to anhydrite. 



From a search among the minerals of West Paterson and Great 

 Notch it has been found that babingtonite is less rare than had 



