GEOLOGY OF THE NEW YORK CITY AQUEDUCT 



i6i 



3 HOLES BORED UNDER AGREEMENT NO. 44 



No. 

 A 44 



Surface 



1 



■ Rock 



Rock 



f 



Per 





elevation in 



elevation in 



penetration 



cent core 



Kind of rock 



feet 



feet 



in feet 



saved 





»I 



313 -6 



17-4 



167.5 



15 



Slate and sandstone 



l2 



274 



^ 



+ 171-5 



229 .6 



20 



Slate and sandstone 



3 



282 



7 



+ 39-7 



58.8 



14 



Slate 



4 



277 



8 



2 2 .2 



166.7 



26 



Slate and sandstone 



5 



299 



5 



— 47 -o 



50-9 



7 



Slate and sandstone 



6 



279 



5 



40.3 



43 -o 



27 



Slate 



7 



299 



2 



— 51.6 



102 .2 



27 



Slate 



8 



277 





+ 89.0 



109.3 



57.6 



Granite gneiss and 

 quartz 



9 



282 



6 



+ 7.6 



90. 



13 



Slate and sandstone 



10 



230 



S 



— 39-5 



154.7 



49 



Slate and sandstone 



II 



249 



^ 



— 32.5 



93-5 



II 



Slate and sandstone 



12 



272 







— 45- 



58.6 



30 



Slate and sandstone 



13 



288 



4 



—37-6 



79.0 



13 



Slate 



14 



185 



I 



— 39-9 



91.8 



3^ 



Slate and sandstone 



15 



301 



8 



— 59-2 



75- 



45 



Slate and sandstone 



16 



277 



3 



+ 25.9 



104.6 



43 



Pegmatitic granite 



17 



300 





— 42. 



75-2 



Z3 



Slate and sandstone 



^ Porosity test made on hol& no. i shows a loss of .03 gallons of water under 100 pounds 

 pressure with packer at depth of 387 feet. Depth to grjuni water 217 feet. 



Porosity test on hole 2/A44. 



Ground water level at a depth of 90 feet = el. + 184.5', 



SUMMARY 



Depth to packing 

 in feet 





 40 



20 

 60 



40 

 80 



60 

 loo 



80 



120 



100 = Gage pressure 



140 = Calculated pressure^ 



146 



•25 



.20 

 .09 



•37 

 .27 



. 12 



• SO 



• 35 



.16 



.64 



.42 

 .19 



.79 



•52 



• 23 



1.03 = gallons lost 

 • 67 



28 " 



1 06 



247 







^Calculated pressure equals average pressure plus weight of column of water from surface 

 to ground water level. Gage pressure is given in pounds per square inch. Loss is in gallons 

 per minute. 



