382 EEPOKT ON NATIONAL MUSEUM, 1886. 



tiling uow ill tlie market, juul would doubtless find ;i ready sale if 

 once introduced. Other marbles of white or blue-^iiiy color occur in 

 Murphy, and Valley Town, Cherokee County ; Warren Springs, Madi- 

 son County, aud near Marion, in McDowell County. Lack of trans- 

 portation facilities at present is a serious drawback to the introduction 

 of any of these into our principal markets. We have also seen small 

 pieces of very compact deep blue-black crystalline limestone, taking a 

 high polish and suitable for the finest grades of ornamental work, from 

 near iNantehala, Swain County, in this State. Portions of the stone are 

 traversed by a coarse network of pure white calcite veins that greatly 

 added to its beauty. 



remisylvania. — The belt of Lower Silurian limestone that extends from 

 Sadsbury and Bart TowiishiiJS, in Lancaster County, in a general east- 

 erly direction through Chester County, and through the western half 

 of Montgomery County, includes within its area the only quarries oH 

 merchantable marble at present worked within the State limits. Ac- 

 cording to Professor Pogers* this belt forms the bed of a narrow valley 

 some 58 miles in total length, extending from near Abington, in Mont- 

 gomery County, to the source of Big Beaver Creek, in Lancaster County. 

 The lirevailing colors of the stone throughout the larger portion of this 

 area are yellowish or bluish, and it is, as a consequence, suitable only for 

 making quicklime or for ordinary rough building purposes. On the 

 southern side of the valley, however, between Brandywine and Wissa- 

 hickon Creeks, the stone has become highly metamorphosed and con- 

 verted into a crystalline granular marble, white or some shade of blue in 

 color, though often variously veined or mottled. All the quarries as yet 

 opened are situated in Montgomery County, on the steeply upturned or 

 overturned edges of the outcrops within half a mile of the southern 

 edge of the formation between Marble Hall and the Chester County 

 line. 



It is stated that quarries were first opened here about the time of 

 the Pevolutionary war, and that up to 1810 this stone was the favorite 

 and almost only material used in the better class of stone buildings in 

 and about Philadelphia. At about the latter date increased facilities 

 for transportation brought the better varieties of eastern marbles and 

 other stones into competition with it and its use has as a consequence 

 considerably diminished. Among the imjiortant builtlings constructed 

 of the stone during its popularity were the United States customhouse 

 and mint, the Naval Asylum, and Girard College, while the seemingly 

 endless rows of red brick houses with the white marble steps, door 

 and window trimmings are even now as characteristic of Philadelphia as 

 are the brown-stone fronts of New York City. 



The sarcophagi for General and Martha Washington, at Mount Ver- 

 non, are also of this material. While the Montgomery County stone 



* Eep. of First Geol. Surv. of Penua., Vol. I, p. 211. 



