284 INDEX. 



Norfolk County basin, rocks of, 274-275. 



Norian system, relations to Laurentian and Huronian in New Brunswick, 20. 



See Naugus Head series. 

 Nova Scotia, geology of, 163. 



Paleozoic basins of Eastern Mass., 181. 



probably not connected in past time, 182-183. 

 Paleozoic formations of New England, 1. 

 Paleozoic rocks of Eastern Mass., mode of occurrence, 181. 

 Paradoxides Harlani, 183, 195, 208. 

 Paradoxides quarry, 192, 193. 

 Petrosilex, 45-101. 



analyses of, 57, 58, 63, 71, 72, 73, 74, 75, 76, 77, 79, 80, 81, 91. 

 banding of, 56-57, 65-71. 

 concretionary structure in, 57-63, 82-86. 

 definition of, 45-47. 

 distribution of, 94-95. 

 extravasation of, 51-52, 66-70. 

 in Hingham and Plymouth, 91-93. 

 in the Blue Hills, 89-91. 

 in Saugus, 76. 

 origin of, 97. 



pebbles in, 50-52, 65-71, 80-81, 84-87, 92. 

 physical characters of, 93. 

 pinite in, 269-270. 

 prismatic jointing in, 80. 



relations to granite, 31, 33, 73, 80, 82, 89-91, 95-101. 

 relations to Shawmut group, 47-55, 77, 78. 

 stratification of, 57, 63-71, 89, 94, 106. 

 Petrosilex breccia, relations to petrosilex, 47-55. 

 Pinite, analyses of, 270-271. 



geological relations of, 271-272. 

 in conglomerate, 89, 220, 221, 271. 

 mode of occurrence of, 269-270. 

 origin of, 220. 

 See Conglomerate. 

 Porphyry. See Petrosilex. 

 Primordial series, 183-273. 



alteration of by amygdaloid, 198, 247, 248. 



alteration of by intrusives, 193, 195, 262, 267. 



disturbance of, 196-197. 



estuary deposits of, 251-252, 262. 



exotics in, 196-198, 210, 213, 262. 



faults in, 196, 198, 199, 242-243, 244, 245, 246, 258, 259, 268. 



ferruginous beds of, 251-252. 



folds in, 196. (See plates 4 and 5.) 



in Blue Hills, 276. 



in Medford, 259-260. 



quartz veins in, 211. 



relations to crystallines, 11, 266-267. 



