1892.] natural sciences of philadelphia. 445 



December 6, 



The President, General Isaac J. "Wistar, in the chair. 



Fifty-eight persons present. 



Papers under the following titles were presented for publication : — 



" Notes on Monarda fistulosa." By Thomas Meehan. 

 " The Phenomenon of Fertilization in the Flowers of Monarda 

 fistulosa." By Ida A. Keller. 



The supposed South Chester Valley Hill Fault. — IMr. Theo. D. 

 Rand remarked that in the Final Report of the Second Geological 

 Survey of Pennsylvania, p. 174, the following occurs: "In Mont- 

 gomery County the North Valley Hill belt of quartzite undoubtedly 

 continues beneath the Schuylkill, on the same nearly east course, 

 nearly to the Bucks County line .... runs on six miles into 

 Moreland township. Here it ends, spooning to a point, and then 

 sweeping round the east spoon point of the lime-stone ... it 

 returns westward as the south border of the limestone to the 

 Schuylkill, at Conshohocken ;" and on the same page in a foot note: 



" Here the South Valley Hill begins and runs west into Lancaster 

 County. We should, of course, suppose that this southern barrier of 

 the synclinal limestone valley would be made by the quartzite. 

 But it is made of hydromica slate. Repeated reports have been 

 made during tlie last fifty years of the discovery of the quartzite 

 ( ' Potsdam sandstone ' ) at various points along the South Valley 

 Hill; and no doubt specimens of quartzite have been picked up, 

 and even thin outcrops of thin quartzite beds among the slates have 

 been seen. But these amount to nothing. They cannot be accepted 

 as expressing with any certainty the reappearance of the North 

 Valley Hill belt on the South Valley Hill side of the limestone. It 

 looks as if the North Valley Hill rocks descend against a great 

 fault, running along the foot of the South Valley Hill, and are 

 there entirely cut ofi' by it, probably thrown by it ( in company 

 with the lower limestone beds, ) high into the air on the Delaware 

 side of the fault. 



" Now it is just at Conshohocken that the Schuylkill River breaks 

 out of the Chester County Limestone Valley to find its way to the 

 sea, viz., in the short interval between the east end of the hydrom- 

 ica belt of the South Valley Hill coming from the west, and the 

 west end of the southern quartzite outcrop coming from the east. 

 What does this mean ? Surely it is an added proof of a great 

 fault ; and of the total diflference of the two formations ; and of the 

 futility of all endeavors to discover a southerly synclinal rise of the 

 quartzite along the South Valley Hill." 



