INDEX TO GEOLOGY OF THE NEW YORK CITY AQUEDUCT 279 



Formations, summary^ of, 54-57. 



Foundry brook, 27 ; rock condition 

 at, 163-69. 



Foundry brook valle}^ structural de- 

 tail, 165. 



Garden quarry, 198, 199. 



Geographic features, 30-31. 



Geographic history, 65-74. 



Geologic conditions affecting the 

 Hudson river crossing, 97-107. 



Geologic knowledge, practical appli- 

 cation to engineering plans, 19. 



Geologic problems of the aqueduct, 



Geology of region, 29-74 ; summary 

 of formations, 54-57; outline of 

 history, 62-65 \ local summar}^ 265- 

 66. ' . 



Glacial drift, Z'^-Z^, 54> 100, 202. 



Glacial period, 64, 71. 



Gneisses, 176; dioritic, 198, 199; 

 Grenville series, 50-52, 57. See 

 also Highland gneiss. 



Grabau, A. W., cited, 37, 44. 



Granites, 99, 100, 106; gneissoid, 

 198; of the new Ferris quarry, 198. 



Grassy Sprain valle}', 203. 



Gravel, no. 



Gravel hillocks, no. 



Gravel streaks, 111-12. 



Grenville series, 50-52, 57, 62. 



Hamilton shales, 38, 55, 78, 119, 126, 



140, 

 Harbor hill moraine, 35. 

 Harlem river crossing, 237, 238-44; 



map showing plan of exploratory 



borings, 239. 

 Hartnagel, cited, 44; mentioned, 154. 

 Healey, John R., acknowledgments to, 



6; exploratory work by, 237. 

 Henry street, interpretation of hole 



No. 207 on, 261-65. 

 Hester street, interpretation of hole 



No. 202 on, 259-61. 

 High Falls, 125, 127, 133. 



High Falls shale, 44, 55, 126, 133, 134. 

 135; porosity, 135. 



Highlands, 30-31, 73, 81 ; crystal- 

 lines south of, 47, 56; postglacial 

 faulting, 272. 



Highlands gneiss, 50, 57, 99, 102, 154, 

 163. See also Fordham gneiss. 



Highlands group, crossings, 97, 103- 

 4, 105 ; more defensible as a route 

 for the aqueduct line, 103. 



Hill View reservoir, 215; elevation, 



17. 



Hipparionyx proximus, 41. 



Hobbs, mentioned, 95. 



Hogan, Thomas H., assistant di- 

 vision .engineer, 125. 



Hornblendic gneiss, 263. 



Hudson river, 69; water to be used 

 for lire protection, 10; wash bor- 

 ings, 26; depth of buried channel, 

 89 ; submarine channel, 90-91 ; 

 Storm King-Breakneck mountain 

 profile, 91-95 ; origin of the present 

 course, 95-96; crossing, geological 

 conditions affecting, 97-107; out- 

 line map showing possible cross- 

 ings, 98; difference of structure 

 in crossings, 104; postglacial fault- 

 ing of district, 272. 



Hudson river canyon, 81-96; points 

 of exploration, 83-88; comparative 

 sections at Peggs point and Storm 

 King, 92 ; study of profile, 94. 



Hudson River slates, 46, 56, 83, 100, 

 102, 103, 126, 135, 137, 140, 149, 

 153, 154, 272. 



Hudson schist, 201. 



Hurle}^ 127. 



Idlewild, 154. 



Igneous types, 52-54- 



Imperviousness and insolubility, 138- 

 39. 



In wood limestone, 47, 49-50, 56, 172, 

 185, 191, 192, 201, 202, 210, 212, 

 217, 218, 219, 220, 221, 226, 232, 

 237, 238, 240, 242, 243, 245, 246, 

 249, 254, 255, 256, 261, 262, 265. 

 268, 269. 



