GEOLOGY OF DELAWARE CuUNTY. 41.1 



AsBESTUS. That silky variety known as amianthus, is most abundant at Blue 

 Hill. The lij^niform variety is most plentiful in Middletown ; but the 

 mineral can be obtained in some form at most of the exposures of ser- 

 pentine. 



Maonesitk. At most of the exposures of serpentine, a mineral is found that 

 passes under this name. 



Talc. This mineral also abounds in the serpentine or in the subjacent strata. 

 It passes into a kind of soapstone, north of Palmers mill, in Marple. 



PiCROLiTK. Found at several of the serpentine exposures in the County. In 

 Radnor, near the Yellow Spriusfs road, it is of a dark preen color. 



Andalcsite. In Upper Providence, near the Rock House, and in Springfield, 

 half a mile north of West Dale. 



Sillimanite. Was found in one of the stone quarries near Chester. 



Garnet. Large crystals of this mineral have been found in Middletown. nearly 

 op[)osite Bishop's mill, with replaced angles. Common garnets of 

 moderate size are found in the (juarry of Dr. George Smith, in Upper 

 Darby, and on the Pritchett farm, in Haverford. Those of a small size, 

 in immense numbers, exhibiting the appearance of dark-colored gravel, 

 cover the bed of the road east of Friends' Meeting-house, Flaverford. 



HoRNBLEXDK. Near Crura Creek, in Newtown, and at various other places in 

 the County where trappean rocks abound. 



Pyrope. In Concord township, on Green's Creek, above Peter's mill-dam. 



Chrome Ore. This valuable mineral is found in all the large exposures of 

 serpentine in the County, but only in that of Middletown in sutticient 

 quantities to be worked to advantage. The manner of washing the ore 

 is explained in a note page 411. 



Brown Hematite. Found in connection -with all the large exposures of ser- 

 pentine. 



Magnetic Iron. On the Yellow Springs road, in Radnor. 



Plumbago. Very impure, is found in the Lawrence road, on the hill west of 

 Langford Run. 



Sulphuret of Molybdena. In an old mine on Chester Creek above Upland. 



Ferruginous Sulph. Copper. Same locality. 



Bog Iron Ore. This is found in difi'erent deposits of clay throughout the 

 County. Good specimens are found in the clay land north of Darby. 



ZoisiTE. Found in the broken stone on the Delaware County turnpike, nt^ar 

 Abram Powell's dwelling. 



Pipe Clay. At the old lime quarry in Birmingham. 



Apatite. Ridley, in Garnet. 



Schorl. Found in large granitic veins, where they occur; in aggregated masses 

 of crystals northeast of the Rock House, iu Upper Providence. 



OoHREOUs Clay. This deeply tinged yellow clay is found in the bed of the 

 Delaware River, between Hood and ebb tide, just below the Tinicum 

 hotel. This clay is doubtless referred to by Campanius, when he savs : 

 "on the shore of 7V/i/ia^o«^5, there is found a gamboge which is as 

 good as yellow ochre ; but it is not used in the country, except to color 

 deer skins." p. 51. 



Spinelle. In minute octohedral crvstals, at Blue Hill. 



