﻿GEOLOGY OF THE NEW YORJC CITY AQUEDUCT 

 3 HOLES BORED UNDER AGREEMENT NO. 44 



l6l 



No. 

 A44 



Surface 



Rock 



Rock 



Per 





elevation in 



elevation in 



penetration 



cent core 



Kind of rock 



feet 



feet 



in feet 



saved 





»I 



S^LS- 6 



—17.4 



167.5 



15 



Slate and sandstone 



*2 



274.5 



4-I7I.5 



229 . 6 



20 



Slate and sandstone 



3 



282 . 7 



+ 39-7 



58.8 



14 



Slate 



4 



277 .8 



— 22 . 2 



166.7 



26 



Slate and sandstone 



5 



299-5 



— 47 -° 



50-9 



7 



Slate and sandstone 



6 



279-5 



— 40.3 



43-0 



27 



Slate 



7 



299.2 



—51-6 



102 . 2 



27 



Slate 



8 



277. 



+ 89.0 



109.3 



57-6 



Granite gneiss and 



quartz 

 Slate and sandstone 



9 



282.6 



+ 7-6 



90. 



x 3 



10 



2 3°. 5 



—39-5 



154-7 



49 



Slate and sandstone 



11 



249-5 



— 3 2 -5 



93-5 



11 



Slate and sandstone 



12 



272.0 



—45- 



58.6 



3° 



Slate and sandstone 



13 



288.4 



—37-6 



79.0 



13 



Slate 



14 



185. 1 



— 39-9 



91.8 



3 2 



Slate and sandstone 



15 



301.8 



—59.2 



75- 



45 



Slate and sandstone 



16 



277-3 



4-25.9 



104.6 



43 



Pegmatitic granite 



17 



300. 



— 42. 



75-2 



33 



Slate and sandstone 



1 Porosity test made on hole no. 1 shows a loss of .03 gallons of water under 100 pounds 

 pressure with packer at depth of 387 feet. Depth to ground 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 

 ioo 



80 



120 



100 = Gage pressure 



140 = Calculated pressure 1 





.25 

 . 20 



.09 



• 37 

 .27 



. 12 



• So 



• 35 



.16 



.64 



.42 

 .19 



.79 



•52 



.23 



1 .03 = gallons lost 

 .67 



28 " 











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 gallon s 

 per minute. 



