NATURAL SCIENCES OF PHILADELPHIA. 113 



in the Hornblend rocks of Chester County, the texture of the Feldspar and the 

 reflecting plates being peculiar. I propose for it the provisional name of Cas- 

 sinite, Mr. John Cassm having first called my attention to this glassy, bluish- 

 green Feldspar. The possession of the reflecting plates had not been observed 

 until I had discovered it by an examination with the microscope, but which 

 when pointed out may be seen by the naked eye. 



A gray satin-like specimen of Delawareite exhibited no red reflections, but 

 there were some small, black, microscopic crystals chiefly of very elongate 

 hexagons ; some were irregular and not long. 



A green and red mottled Feldspar from Mineral Hill, near Media, presented 

 reddish groups of reflections here and there throughout the mass. Under a 

 high power these plates were observed to be of the usual modified forms of 

 the hexagon, that of the rhomboid prevailing while the hexagonal form itself 

 was found only in rarer instances. The color of these plates varied from a 

 blood red to a pale wine red, and are very small and numerous. This is a 

 remarkably beautiful mineral and is I believe very rarely now found. I have 

 found a single specimen and the only other specimens I have seen, were 

 found some thirty years since. 



In the beautiful Sunstone of Chester County, near Kennett Square, I found 

 many reflecting plates of various shades of red. These plates are very numer- 

 ous and usually elongate rhomboids, but the hexagonal form and all its modi- 

 fications are found of various sizes when examined with a high power. There 

 were observed also many black irregular spots, and some of these had irregu- 

 lar hexagonal margins. Interspersed throughout could be seen very numer- 

 ous short, black, attenuate, prismatic forms, much more numerous and ap- 

 proximate to each other than was the case with the reflecting plates. 



The fine Sunstone of Arendal, Norway, presents very remarkable reflections 

 of not very minute plates. The Feldspar is clear and pure, and these reflec- 

 tions numerous and very brilliant. The hexagonal form and its modifications 

 are very perfect, and the color pure and translucent, varying from dark red 

 to light wine color. Many of the rhomboids are very elongate. Occasionally 

 opake black plates were observed, and the same may be said of other Sun- 

 stones generally. 



Chesterlite, from Chester County Poor House, quite to my surprise, presented 

 here and there hexagonal plates. In one specimen I detected a remarkably 

 fine hexagon of a deep red color. 



Perthite, from Perth, Canada West, is a very dark salmon-colored variety 

 of Sunstone. and I found in it the same hexagonal form and its modifications, 

 but the plates were darker in color. There were mixed with these some 

 opake black ones, similar in density and form to those which are found in 

 the Sunstone of Chester County. 



In Peristerite, from the same locality, I found very numerous minute black 

 crystals, generally elongate rhomboids, very like, if not toe same with, com- 

 mon Labradorite, to which it seems to be very nearly allied. 



Observations on CHAEIETES and some related Genera, in regard to their Sys- 

 tematic Position ; with an appended description of some New Species. 



BY DR. CARL ROMINGER. 



Chaetetes has, by its tubular structure and the transverse diaphragms, di- 

 viding the tubes, a strong resemblance to Favosites, and was for this reason 

 generally considered to be a member of the Favositoid family. 



In the following pages I shall try to prove this to be an error, and to de- 

 monstrate its immediate connection with forms which are considered to be 

 Bryozoa. 



It has been asserted that transverse diaphragms have never been observed 1 



1866.] 8 



