10 On the Mineralogy of Chester County, Perm. fyc. 



Plumbago, in quartz, near Charleston village, Charleston 



township. 

 Epidote, in hexahedral prisms, of a yellowish green color, 



Strode's mill, near West Chester. 

 Oxide of iron, highly magnetic, near Goshen meeting house, 



East Goshen township. 

 Garnets, in dodecahedral crystals, of abrown color, abundant 



on A. Hoope's farm, East Goshen township. 

 Bog iron ore, on Pennypacker's farm, Charleston township. 



Little Britain Township, Lancaster County, Perm. 



Octahedral magnetic oxide of iron, on the serpentine ridge, 

 on Joel Jackson's farm. 



Massive and crystallized ferruginous oxide of chrome, or 

 chromate of iron, occurs on a minor ridge of serpentine, 

 about a mile north of the main serpentine ridge, being 

 about two miles west of the south western point of Chester 

 county, on the property of McKim, Sims, & Co. of Balti- 

 more, adjoining Joel Jackson's farm. The disintegrated 

 crystals of chromate of iron, are found coating the cavities 

 of all the ravines made in the sides of the hill, and indicate 

 the existence of this valuable material in quantity. 



Magnesite. An extensive locality of this valuable mineral oc- 

 curs, forming veins in the serpentine of considerable thick- 

 ness, same locality ; and is now extensively quarried and 

 manufactured by Messrs. McKim, Sims, & Co. of Balti- 

 more, into sulphate of magnesia, (Epsom salts.) These 

 gentlemen have succeeded in making a purer salt at a 

 much less price than it can be imported, which has entire- 

 ly excluded importation ; and the United States are now 

 almost entirely supplied from this establishment. Four 

 hundred or five hundred tons of magnesite, have been ob- 

 tained from this locality, and Messrs. McK. & S. manufac- 

 ture 1 ,500,000 lbs. of Epsom salt annually. 



Actynolite, in green compressed crytals, in talc, serpentine 

 ridge, on Joel Jackson's farm. 



Noble serpentine, with delicate veins of amianthus, serpen- 

 tine ridge, on Joel Jackson's farm. 



Chalcedony. An interesting locality of this mineral occurs 

 near the magnesite above described, and about one and a 

 half miles distant from the celebrated locality at Rocks 

 springs, described in my former paper, and near the local- 

 ity of magnesite and chromate of iron. 



