1892.] NATURAL SCIENCES OF PHILADELPHIA. 181 



hornblende gneiss to quartzite. This quarry only, among the large 

 number in the porphyritic rock and adjacent schists, is worthy of the 

 name of a mineral locality ; no fine specimens were found, but the 

 following occurred : quartz in modified crystals, epidote, mag- 

 netopyrite, calcite in dog-tooth crystals, krokidolite,- garnet, 

 laumontite. and coatings of halotrichite. On one occasion the sap 

 from a broken I'oot of an oak in the soil over the quarry had trickled 

 down over the rocks whence the halotrichite effloresced, forming a 

 black band of native ink. Rhodonite is reported to have been 

 found in this quarry but I have not seen it. 



Northwest of the Manayunk schists is another series, termed by 

 Mr. Hall the Chestnut Hill schists. Both series contain numerous 

 garnets but the Chestnut Hill schists contain them in largest quan- 

 tity. They are very abundant, sometimes crystallized, rarely large, 

 always dull and usually rough. 



In both these schists occur outcrops of magnesian rocks. The 

 most important of these, mineralogically, except possibly the out- 

 crops near Media, is that which is known as the steatite belt which 

 extends from Chestnut Hill, Philadelphia, to Bryn Mawr. It is 

 well exposed on the Wissahickon but on the Schuylkill, at the 

 northwesterly line between Philadelphia and Montgomery County, 

 it has been largely quarried for over a century and has yielded 

 quite a variety of minerals, as follows: talc, rarely in crystals, 

 abundant massive and sometimes in beautiful green translucent 

 specimens ; dolomite, massive very abundant, sometimes good 

 cleavage specimens associated with talc are obtained ; it occurs 

 also crystallized in the ordinary form of pearl spar, of which some 

 beautiful specimens have been obtained, also in six-sided prisms 

 with terminations, and rarely in a form veiy near a cube ; breun- 

 nerite, in poor specimens, at the old soapstone quarry on the east 

 bank of the river, but in crystals quite perfect and more than an 

 inch across, at the quarry on the west bank ; magnetite in octahedra 

 in chlorite ; tremolite, actinolite, chlorite, hallite, staurolite, mil- 

 lerite, bornite, chalcopyrite, malachite, chrysocolla, maguetopyrite, 

 garnet, apatite, genthite, epsomite, chalcanthite, aragonite, zoisite, 

 pyrophyllite, barite and one specimen of rutile in dolomite. Asso- 

 ciated with the steatite is a rock occurring in vast quantity, the 

 mass being steatite, with apparently nodules of serpentine scattered 

 through. At times these show the crystalline form of staurolite, and 

 they are, in part at least, pseudomorphs of serpentine after staurolite. 



