I20 



NEW YORK STATE MUSEUM 



Peet, C. E., cited, 102, 115. 

 Pegg's Point, 97, 99. 

 Petraia corniculum, 62. 

 Petrographic character of the rock, 



influence of, 106. 

 Petrography of the gneisses, 14-18. 

 Phacops sp., 67. 

 Pierce, James, cited, no. 

 Plagioclase, 15, 16, 18, 23, 31. 

 Platyceras, 49. 

 Platynotus trentonensis, 67. 

 Pleasant Valley, 8, 59, 63, 91; lime- 

 stone masses east of, 89. 

 Plectambonites sericeus, (ij, 83, 84. 



See also Leptaena. 

 Pleurotomaria, 60. 

 Postglacial erosion, 104-5. 

 Potsdam formation, 49-51, 59, 64, 



109. 

 Poughkeepsie, 6, 99, 109. 

 Poughquag quartzite, 11, 39-47. 

 Precambric gneisses, 11. 

 Preglacial history of drainage, 96- 



99. 

 Ptilodictya acuta, 61. 

 Ptychaspis, 49. 

 Ptychoparia (Conocephalites), 49. 



sp., 50. 



calcifera, 49. 



saratogensis, 49. 

 Pumpelly, cited, 115. 

 Pyrite, 38. 

 Pyroxene, 38. 



Quartz, 15, 16, 17, 18, 23, 27, 31, 32. 

 Quartzite, 27, 38, 39; basal, 39-47; 



near Rochdale, 86. See also 



Poughquag quartzite. 



Receptaculites, 61. 



Red slates, 85. 



Rice, W. N., cited, 115. 



Ries, H., cited, 108, 115. 



Rochdale, 8, 57, 59, 60, 62, 63, 64, 86, 



91, 103. 

 Roseton, loi, 102 ; clays, 107, 108. 

 Ruedemann, R., cited, 65, 115. 



Salter, J. W., cited, in. 

 Schuchert, Charles, cited, 115. 



Sericite, 23, 31. 



Serpentine, 38, 39. 



Shenandoah, 25, 109. 



Shenandoah mountain, 7, 13, 24, 3S> 



42, 99. 

 Shenandoah mountain granite, 11, 



17-18. 

 Slate formation, 85, 96. 

 Smock, J. C, cited, 11, 26, 113, 114. 

 Soils, 107. 

 Solenopora compacta, 50, 51, 52, 62, 



63, 67, 68, 75, 76, 91- 

 Sprout creek, 8, 88. 

 Stoneco, 52, 55, 56. 

 Stoneco quarry, 108. 

 Storm King, 97, 98. 

 Stormville, 80. 

 Stratigraphical table, 11. 

 Streptelasma sp., 67. 

 Stromatocerium, 49. 

 Stromatopora compacta, 62. 

 Strophomena alternata, 61, 67, 7S, 



83. 

 Swartoutville, 73, 76, 84, 92. 

 Sylvan lake, 8. 



Terraces, loi. 



Tertiary upHft, 97. 



Tetradium cellulosum, 62, 65. 



Titanite, 31. 



Titusville, 68. 



Topography, 7. 



Trenton formation, 51-56, 59, 61-62, 



65, 71, 75- 

 Triplecia, 59. 



Ulrich, E. O., mentioned, 56; cited, 



115. 

 Upham, W., cited, 114. 



Valleys of the Tertiary cycle, 96. 

 Van Hise, C. R., cited, 114, 116. 

 Vly mountain, 11, 26, 27, 30, 33, 40, 



71, 72. 



Walcott, C. D., cited, 56, 113, 114. 



Wappinger creek, 8, 98, 103, 104, 105. 



Wappinger creek belt, western strip, 

 48-56; central strip, 57-65; faulted 

 blocks, 65-70; limestone quarries, 

 108. 



