Trans. N. V. Ac. Sci. 50 Jan. 14, 



It may be described as consisting of interlaced fibres of asbestos, 

 the leathery tint due to impurities. 



A number of visits have been made to the quarries at Weehawken. 



The trap rock of this locality affords specimens of a mineral, the 

 nature of which has not yet been ascertained. It is possibly of a 

 chloritic nature. One is reminded of the investigations of Prof. 

 Israel C. Russell on certain hydro-carbons found by him near 

 Plainfield, N. J., also of the mineral of the Connecticut ttap dikes 

 described by G. W. Hawes under the name " Diabantite." 



The specimens obtained at Weehawken are light in weight and 

 readily disintegrated. One variety is black in color — resembling 

 asphaltum — the other is of a steel-blue tint. 



At the northern extremity of the quarries is found a close-grained 

 trap known as aphaniie, which exhibits interesting illustrations of 

 radiated structure, and rounded forms with conchoidal fracture, pecu- 

 liar to concretionary developments of certain minerals. 



In the drift overlying the trap I was successful in finding some re- 

 markably good specimens of Graphite, much superior to any yet ob- 

 tained in the vicinity of our city. 



DISCUSSION. 



Dr. JULIEN remarked that the dark chlorite, however carbona- 

 ceous in appearance, owed its color entirely to mineral matter, accord- 

 ing to all analyses yet made. It belonged to the group of so-called 

 minerals — delessite, diabantite, etc. — -whose want of uniformity in com- 

 position and absence of crystallization marked them as transformation 

 products in the alteration of the original augite, etc., of the diabase. 

 The specimens of decayed micaceous mineral exhibited were identical 

 in appearance with Jefferisite, Culsageeite, etc., a series of more or less 

 oxidized forms of an altered chlorite from Pennsylvania and North 

 Carolina, to which a long list of unnecessary new names had been 

 recently given. 



Mr. G. F. KUNZ observed that the darker form of chlorite found at 

 Weehawken differed much in appearance from that found elsewhere 

 in the range. Some of it was light green in color, but this was as dark 

 as a hydro-carbon and very brittle, evidently consisting of portions of 

 the rock, thoroughly altered. 



Mr. Chamberlin further stated that radiated forms of this chlorite 

 were often seen. 



Dr. Brixton had noticed faults in the rock, at 117th Street and 

 Fifth Avenue, at right angles to the bedding, and lined with a slick- 

 ensides of chloritic material. 



