fenner: babingtonite from passaic county 599 



of zeolitic minerals found at various localities in the Watchung 

 basalt sheets of northern New Jersey. Mention was made 

 of the presence of certain remarkable cavities or casts of some 

 mineral formerly present, which are very abundant in the de- 

 posits and which have been a source of much speculation among 

 mineralogists for many years. It was believed that the evidence 

 indicated that the origin of the casts was to be ascribed to bab- 

 ingtonite. Since the article was written certain new evidence 

 has come to light which has an important bearing upon the subject. 



Through the kindness of Dr. W. T. Schaller of the United 

 States Geological Survey my attention has been directed to two 

 recent discoveries. One of these was reported in an article in 

 the New York Times for November 23, in which Mr. F. I. Allen 

 of New York described the discovery of anhydrite at West 

 Paterson and ascribed to this the role of the parent mineral of 

 the casts. At about the same time or a little before, an un- 

 published discovery was made at McKiernan and Bergin's quarry 

 in Paterson of pseudomorphs of quartz occupying certain of the 

 cavities. These pseudomorphs were remarkable for the fact 

 that they were loose in the cavities and could be easily withdrawn, 

 but nevertheless showed sharply defined prismatic faces and 

 less distinct terminal faces. The presence of these faces suggested 

 that a comparison of the crystal angles with those of known 

 species might serve to establish the identity of the original 

 mineral. 



Since the appearance of the previous article I have received a 

 number of inquiries regarding the occurrence of babingtonite 

 from mineralogists who have been interested in the casts, and 

 some question has been raised as to the quantitative importance 

 of this mineral in the formation of the cavities. Its identification 

 as babingtonite appears to have been accepted, but some doubt 

 has been expressed as to whether it was present in large amount 

 and as to whether most of the cavities should not rather be 

 ascribed to anhydrite and a possible thu-d mineral of unknown 

 nature. For these reasons and on account of the importance 

 of the new finds it seemed desirable to revisit the localities of 

 discovery, to examine all available material, and to present a 



