476 MINLHALS IN THE rdecembetv 



Adularia, 



This variety of Feldspar, occurs in the hornbIend« 

 Focks, of the quarry, end of canal road. Some specimens 

 are distinctly crystallized. 



Desintegrated Feldspar. Kaolin. 



Feldspar in a state of decomposition exists on the ca- 

 nal road, 'And on Mill creek, near the Baltimore turnpike^ 

 and in large quantities about three miles west of Chester^ 

 near the creek. 



Claz/, 



Nature has abundantly supplied us with this sub- 

 stance^ so useful to the manufacturers of porcelain. The 

 numerous kilns for the burning of bricks, sufficiently point 

 out the situation where it is most plentiful. A more pure 

 variety of clay, is found on the Delaware below Borden- 

 town, and thence to Newcastle. Large quantities are 

 taken in waggons to Pittsburg, a distance of more than 

 three hundred miles, used by glass blowers, for making' 

 pots. Variegated clay is also found near Bordentown. 



Mica, Glimmer, W. 



This occurs exceedingly abundant in the primitive 

 formation of our neighbourhood. We find it in hexae- 

 dral prisms and tabulated, on the Schuylkill, near Ger. 

 mantown, and on the Wilmington road near the Wood- 

 lands, where I have found hexaedral crystals of black 

 mica, circumscribed by those of a light brown, forming 

 curious specimens. The largest plates I have seen, of this 

 vicinity, were found by Mr. Vanuxem and myself about 



