1S91.] **y [Carter and Lesley. 



10' Mica schist ; quartz, biotite, muscovite 220' 



10 Mica schist ; biotite, quartz, muscovite 2:30 



20 Mica schist ; biotite and quartz 250 



15 Mica schist ; biotite, muscovite, quartz 205 



Few crevices ; strata tightly packed ; first rock water struck at 120 ; 

 rose to 28' beneath surface ; pumped 5 quarts a stroke, 80 strokes a min- 

 ute, 0000 gallons an hour ; level falls 20' after one hour's pumping. 



Water a little hardened by sulphates and some iron. 



Artesian Well in Mica Schist, near Radnor, Delaware County, Pa. 



Notes by 0. G. S. Carter. 



Drilled on M. Wheadley's farm, in Chester county, Pa., in the hydro, 

 mica schist of the South Valley Hill belt. 



30' Sharp white quartz fragments to 30' 



58 Schist, very micaceous, silver gray, soapy 88 



"Water crevices struck at 70 and 85 ; water rose only 10 feet in the well, 

 and stood at 70 feet below the surface ; yield, only 120 gallons per hour ; 

 drops 5 feet after pumping five hours. 



Feldspar Bed in Laurentian (?) Gneiss. 



By Prof. Oscar G. S. Carter. 



(Read before the American Philosophical Society, May 1, 1S91.) 



The feldspar quarry is opened on the east bank of the Schuylkill river, 

 between Lafayette Station and Spring Mill, where the Reading Eailroad 

 (Norristown branch) and the Pennsylvania Railroad (Schuylkill Valley 

 division) run side by side under the bluff outcrops of syenite and gneiss 

 supposed to be of Laurentian or Archaic age, bordered on the south by 

 C. E. Hall's Chestnut Hill Mica Schist belt of undetermined age. 



A small stream cutting down into the Schuylkill just south of the 

 quarry marks the contact of the mica schist and syenite and gneiss belts. 

 About 100 yards north of the quarry is the granite vein described in Prof. 

 H. D. Roger's Geology of Pennsylvania, 1858. 



The county road runs between the railroad tracks and the bluff, and the 

 feldspar bed is quarried for 35 feet alongside of the road. The feldspar 



PROC. AMER. PHILOS. SOC. XXIX. 135. G. PRINTED JUNE 5, 1891. 



