USEFUL METALS J,l 



differentiation in northern Vermont and Megantic County. 

 (Quebec. The mines in the Canadian territory an- .-till worked, 

 but those in Vermont are idle, although a considerable amount 

 of ore was at one time mined in the town of Troy. The larger 

 ore bodies of Pennsylvania lie in the same peridot it e belt and 

 possess the same mode of origin. J. H. Pratt has attuned 

 magmatic segregation to the chromite deposits of the southern 

 Appalachians. Chrome ocher may result from the alteration 

 of chromite. 



Character of the Ore Bodies. Chromite occurs in irregular 

 pockets, veins, and lens-shaped masses segregating near the 

 periphery of a peridotite magma. It is also found in placers in 

 association with platinum where it has been derived through tin- 

 decomposition of peridotite. 



Geographical Distribution. There are two distinct belts of 

 chrome iron ore in the United States: The Appalachian dis- 

 trict and the California district. 



The first of these districts may be subdivided into three dis- 

 tinct fields. The southern lies in north Carolina and Maryland; 

 the central has reached its best development in Pennsylvania 

 and the third in northeastern Vermont and Canada. Deposits 

 of chromite occur in the western part of North Carolina and- 

 in Baltimore County, Maryland, but these ores are no longer 

 worked. The Wood's mine in Lancaster County, Pennsylvania, 

 was opened in 1828 and worked continuously until 1869, when the 

 mine filled with water. At one time this mine produced practic- 

 ally all the chromite in the world. The ore was also worked at 

 one time in Chester and Delaware Counties, but these mines have 

 also been abandoned. Chromite ores were worked in the early 

 60's in the northeastern part of Vermont, but distance from the 

 railroad led to the abandonment of these mines also. In Megan- 

 tic County, Quebec, and in Newfoundland where the ores occur 

 in the same peridotite belt they are still extensively mined. 



In the California district the deposits of chromite reach their 

 best development in San Luis Obispo and Shasta Counties. In 

 the former county the mines like those of the Appalachian belt 

 have been abandoned. The ores of Shot Gun creek in the latter 

 are still worked for their chrome content. According to H. Ries 

 the ore occurs in serpentine in a series of five lenses, each contain- 

 ing from 200 to 1500 tons of chromite. Each lens is connected by 

 vein-like stringers in a nearly vertical shear zone. The ore con- 



