4 On the Mineralogy of Chester County, Penn. <§-c. 



through several townships. Large quantities of detached crys- 

 tals of beryls, may, at all times, be dug within a foot or two 

 from the surface. Drusy quartz, of white, yellow and rich 

 green colors, occurs in considerable quantity, in the vicinity. 



Westown Township. 



This township was not noticed in the former description, 

 and has been as yet but partially explored ; the following are 

 the most important minerals which have been discovered. 

 Earthy and ferruginous oxide of manganese, of excellent 



quality, for employment in the arts and manufactures. I 



presented a sample to Mr. Abraham Miller, an ingenious 



potter of this city, who made use of it in his manufacture, 



and pronounced it equal to the imported. It occurs on 



Joseph Osburne's farm, three miles south of West Chester. 



It has not yet been worked, but its position and external 



appearances render it probable, that it is abundant. 

 Siliceous oxide and carbonate of manganese, of a reddish 



and yellowish brown color, and of a somewhat foliated 



structure, same locality. 

 Manganesian garnet, massive, of a reddish brown color, 



same locality. 

 Black schorl, traversing quartz in cylindrical crystals, very 



beautiful, on Joseph Osburne's farm. 

 Fine acicular and fibrpus hornblende, of a jet black color, 



same locality. 

 Limpid and smoky quartz, in beautiful transparent crystals, 



hexahedral prisms terminated by pyramids, loose in the 



soil, Joseph Osburne's farm. 



A mine was opened on this farm about sixty years since 

 for silver ore, and a small portion of the metal was obtained. 

 It was however abandoned in consequence of the minute 

 quantity yielded, and a doubtful prospect of its producing 

 advantageously. The oxides and carbonates of manganese, 

 and the manganesian garnet, occur also, on William Os- 

 burne's farm adjoining. 



East Bradford Township. 



Cyanite, in oblique tetrahedral prisms, (primitive form,) from 

 one quarter to one inch in thickness, and from one to three 

 inches in length, occurs in mica slate and detached crys- 

 tals, on the Strasburg road, near the bridge on the east 

 branch of the Brandywine — abundant. 



