464 MINERALS IN THE [December, 



end being replaced with two faces inclined towards each 

 other. It occurs in large quantities in the talc rocks of 

 Chestnuthill, immediately on the Wichicon creek, east- 

 ern side, ten miles from the city. 



Sulphur €t of Iron, Iron Pyrites, W. Fer sulphur e. H. 



In our hornblende rocks we find this mineral, gene- 

 rally disseminated, but sometimes in the form of cubes. 

 It occurs also, at the mine near Chester, and at Perkiomen 

 lead mines, crystallized in various forms, and frequently 

 tarnished so as to present the appearance of other me- 

 tals. 



Brown Oxide of Iron. Hematite. W. Fer oxide 

 Hematite. H. 



This species of iron ore is found at Upper Dublin, 

 about fifteen miles north of the city. It frequently occurs 

 in geodes, the interior sides of which are perfectly black, 

 and of a botryoidal, mammillary or corralloidal form: 

 sometimes the cavity contains sand. Its construction 

 proves it to be concretion. Some specimens have also 

 been foimd on the Schuylkill. 



Scaly red Oxide of Iron, Red Iron Froth, W. Fer 

 oligiste luisant. H. 



At the lead mines on the Perkiomen we find fine spe- 

 cimens of this mineral. It occurs there in scaly particles 

 of a nearly cherry red colour; soft to the touch, and soils. 

 It is taken out of the vein with the lead, generally in 

 crusting some other mJiieral. 



