368 REPORT ON NATIONAL MUSEUM, 1886. 



tlio Chester Biiri-eus, near the town of West Chester. Quarries were 

 first opened hero in 1790, and up to date upward of 500,000 cubic yards 

 of material have been taken out. The rock, as usual, occurs only in a 

 jointed condition, and blocks of large size can not be obtained ; the 

 largest yet quarried measured 3 feet square by 16 feet in length. 



The principal markets for the quarried material are New York, Phil- 

 adelphia, Baltimore, Washington, and Chicago, though it has been used 

 in Philadelphia to a greater extent than elsewhere. The University of 

 Pennsylvania, Academy of Natural Sciences, and about twenty churches 

 in this city are of serpentine. 



Quarries that have been worked in years past occur near the Mary- 

 laud line (Rising Sun post-office), and in Media, Delaware County. The 

 price of the rough stone at tlie quarries varies from 20 to 40 cents per 

 cubic foot, and the cost of dressing varies from 5 to 15 cents per square 

 foot of surface.* A beautiful deep lustrous green variety susceptible of 

 a high i^olish and known as Williamsite was found in abundant small 

 pieces during the working of the Fulton township chromite mines. 

 Excepting as polished specimens for mineral cabinets the material was 

 uever utilized. 



Although the Chester County stone has been upon the general market 

 only about ten years it has already acquired an excellent reputation. 

 To the writer it seems, however, that in the majority of cases v^ery poor 

 taste has been shown on the part of the designers, very many of the 

 buildings being anything but beautiful from an architectural stand-point, 

 Tlie almost universal practice of using a light, yellowish-gray sandstone 

 for the trimmings in houses of this material should also be condemned, 

 since the contrast is not sufficient nor satisfactory. 



The use of the stone in cities has not been long enough continued to 

 furnish accurate data regarding its durability there, but it is stated that 

 houses erected in the vicinity of the quarries one hundred and fifty 

 years ago show the color of the stone to day as fresh as when first quar- 

 ried. The writer's personal observations are, however, to the effect 

 that in a majority of cases many of the blocks exposed in a wall turn 

 whitish, or at least fade to a lighter green. Such a change can scarcely 

 be considered detrimental. 



Vermont— The bed of talcose slate that extends in a general northern 

 and southern direction throughout the entire length of central Vermont 

 bears numerous outcrops of serpentine or of serpentine in combination 

 -with dolomite, but which, so far as the writer is aware, have been 

 quarried in but two localities, Eoxbury and Cavendish. The quarry at 

 Cavendish was worked very early, having been opened about 1835,f be- 

 fore there were adequate means of transportation of the quarried stone 

 or there was any sufficient demand for so expensive a material. The 



• See Geology of Chester County, Vol. C*, Second Geological Survey of Pennsyl- 

 vania, p. 61, et al. 

 t Geology of Vermont, Vol. ii, p. 778-9. 



