GEOPHYSICAL LABORATORY. 157 



dimensions it is apparent that some of the original babingtonite crystals 

 attained a length of 6 to 8 inches. The deposition and subsequent removal 

 of the mineral shows that the conditions of chemical stability were satisfied 

 for a brief period only in the history of the deposits. 



(49) Additional notes on babingtonite from Passaic County, New Jersey. Clarence N. 

 Fenner. J. Wash. Acad. Sci., 4, 599-605 (1914). 



After the appearance of the first article on babingtonite, the localities of 

 discovery were revisited and considerable new material was collected bearing 

 upon the question of the original minerals of the cavities. The results are 

 presented in the second paper. They may be summarized as follows: Both 

 babingtonite and anhydrite were originally present in the deposits and both 

 have been removed to a large degree, leaving cavities which outline the shape 

 of the original crystals. In some instances, the geometric form of the two 

 was so similar that the nature of the original mineral can not be decided from 

 the casts alone. Babingtonite, however, seems to have shown a tendency to 

 develop in a rather tabular shape, and cavities of this kind, especially when 

 showing the projection of many thin laminae, are regarded as more probably 

 due to the latter mineral. The various rectangular cavities seem sufficiently 

 explained by the discovery of these two minerals. 



Other cavities of lozenge-shaped section are of more doubtful origin. The 

 most probable explanation appears to be to regard them as due to babing- 

 tonite of somewhat different development from the first, but the evidence 

 at hand is not yet sufficient to decide definitely upon this point. 



