fenner: babingtonite from passaic county 605 



measured. They appear to indicate monoclinic or triclinic 

 s>Tnmetry, but do not suggest the forms of babingtonite which 

 are figured by Hintze and Dana. Differences in conditions of 

 deposition, however, might cause much variation in this respect. 

 Some indication of the fonner presence of a ferriferous mineral 

 is afforded by the frequency with which these casts are stained 

 red by ferric oxide or are partially occupied by a chloritic 

 substance. 



The conclusions which have been reached regarding the various 

 forms of cavities from a study of the new material and a re- 

 examination of all the available evidence may be summarized 

 as follows: Both babingtonite and anhydrite were undoubtedly 

 present in the deposits and the crystals of each attained a large 

 size. In some instances the geometric form of the two was so 

 similar that the nature of the original mineral cannot be decided 

 from the casts alone. Babingtonite, however, seems to have 

 shown a tendency to develop in a rather tabular shape, and cavi- 

 ties of this kind, especially when showing the projection of many 

 thin laminae, are regarded as more probably due to the latter 

 mineral. The rectangular cavities both of tabular and of nearly 

 square form seem sufficiently explained by the discovery of these 

 two minerals 



The origin of the lozenge-shaped cavities is more uncertain. 

 They may have been occupied by babingtonite deposited under 

 different conditions from those which prevailed during the de- 

 position of the rectangular forms and therefore developing 

 different crystal-faces, or they may be due to some other mineral 

 to whose nature we have Httle clue. It seems necessary to ob- 

 tain more information before reaching a positive conclusion on 

 this point. 



