112 PROCEEDINGS OF THE ACADEMY OF 



In the dark, nearly black Labradorite of the Adiroudac Mountains, there 

 were only to be found dark, irregular, uushaped spots. 



In the nearly black opalescent portions of Labradorite from Warwick, 

 Orange Couuty, N. Y. , were very minute imperfect black crystals, while 

 scattered throughout there are larger transparent, imperfect forms of irregular 

 crystals, which have the appearance of being hollow points. 



A rolled fragment of pale purple Feldspar from Easton, Pa., contained 

 hexagonal plates, but generally these plates were found to be irregular and 

 broken. 



A Black Feldspar found near West-Chester a small fragment nearly an 

 inch square was found to possess very thin prismatic black crystals, lying 

 in various directions, but principally in one direction. There were also 

 scattered throughout a few very black spots, some of which were disposed to 

 take the hexagonal form. 



Labradorite from Scotland, with a fine colored surface, presented minute 

 reflections. Under a high power, a few brown hexagonal plates were 

 observed, with very numerous black, attenuated, prismatic crystals, and 

 some short thick ones. 



A bluish lead-colored glassy Feldspar, from near West-Chester, presented 

 acicular black lines all in the same direction. These were usually somewhat 

 long, much more so than I have observed in any other specimens which I 

 have examined. Occasionally an opake, black, rhombic crystal was 

 observed. 



A dark variety from Lenni, passing into Leelite, possesses very minute 

 black, attenuated prismatic crystals. 



Fetid Feldspar (Necronite ?) from the Vanarsdale Quarry in Bucks County, 

 Pa., has microscopic black crystals, imperfectly formed, but with a tendency 

 to hexagonal form. 



A Salmon- colored Feldspar, from near Lenni, was found to possess many 

 elongate black rhomboids, and some few imperfect reddi&h hexagonal plates. 

 One of the rhomboids is partly black and partly red, showing that the crystals 

 of both colors are of the same substance. 



A specimen of a darker salmon color, found by Mr. John Cassin, many 

 years since, attbe old Molybdena Mine, near Chester, Pa., has the appearance 

 of Perthite, but there were no reflections to be observed in it, only presenting, 

 occasionally, black masses. The deep color of this Feldspar arises from the 

 close approximation of irregular opaque brownish masses. 



A very pearly specimen of Delawareite found near West-Chester, con- 

 tained rather large reddish plates and many opake black crystals, some elon- 

 gate, others triangular, hexagonal, &c. 



Among the pearly specimens of Delawareite from Lenni is a fine purplish 

 one with blood-red crystals, which are much larger than usual, and one is 

 much longer and narrower than usual. In one of the pieces I observed a 

 black curved object which presented a serrated side, reminding one of the 

 notches of a Graptolite. It is probably Tourmaline. 



The remarkable fine Sunstone obtained by Mr. Jetferis and myself in Chester 

 County, Pa., present under a high power a great number and variety of bril- 

 liant red crystals of a hexagonal form, and of every modification of this figure. 

 The reflections of the surface of these crystals give beautiful colors. Occasion- 

 ally in these specimens where the plates are numerous and close, an area 

 may be observed without any color, being clear, but retaining the hexagonal 

 form and its modifications, the area being surrounded by reflections of red, 

 blue, &c. 



In the very peculiar greenish blue, lamellar Feldspar, from Blue Hill, two 

 miles north-west of Media, Delaware Co., I found very numerous, small reflec- 

 tions of the usual modifications of the hexagon. This is a very pure and glassy 

 species, and is of rare occurrence. It is found in the Serpentine rocks, and 

 presents an entirely different appearance from Sunstone proper, which is found 



[May, 



