Penfyhaniay Philadelphia. 83 



the cubes, the planes of the fides only- 

 amounted to a quarter of an inch, but in 

 the biggeft cubes, they were full two inch- 

 es. Some were exceedingly glittering, fo 

 that it was very eafy to be perceived that 

 they confifted of fulphureous pyrites. But 

 in fome one or two lides only, glittered fo 

 well, and the others were dark-brown. 

 Yet mofl of thefe marcafites had this fame 

 colour on all the fides. On breaking them 

 they fhewed the pure pyrites. They are 

 found near Lancajier in this province, and 

 fometimes lie quite above the ground ; 

 but commonly they are found at the 

 depth of eight feet or more from the 

 furface of the ground, on digging wells and 

 the like. " Mr. Heff'eliiis had feveral pieces 

 of this kind of flone, which he made ufe of 

 in his work. He firft burnt them, then 

 pounded or ground them to a powder, and 

 at lafl rubbed them flill finer in the ufual 

 way, and this afforded him a fine reddifh- 

 brown colour. 



Few black pebbles are found in this pro- 

 vince, which on the other hand yields ma- 

 ny kinds oi marble y efpecially a white oney 

 ^with pale-grey bliiijh fpots, which is found 

 in a quarry at the diftance of a few Englijh 

 miles from Philadelphia, and is very good 

 F 2 for 



