XVI TABLE OF CONTENTS. 



XIII. 



THE GEOGNOSY OF THE APPALACHIANS AND THE ORIGIN OP 

 CRYSTALLINE ROCKS. 



The relations of geology to the sciences 240 



PART I. THE GEOGNOSY OF THE APPALACHIAN SYSTEM. 



History of the Appalachian mountain system 241 



Eaton on the classification of rock-formations 241 



Jackson and Rogers on the rocks of New England .... 242 



The Adirondack or Laurentide series ; Laurentian 243 



The Green Mountain series ; Huronian 243 



The White Mountain series; Montalban 244 



Rogers on the crystalline rocks of Pennsylvania 245 



His hypozoic and azoic series probably identical 247 



Crystalline rocks of New York and New England .... 248 



Crystalline rocks of Virginia, the Carolinas, and Tennessee . . . 249 



Emmons on the crystalline rocks of western New England . . . 250 



Note on the decay of these rocks to the southwest 250 



The Taconic rocks of Emmons distinguished from the primary . . 251 



The Taconic system described and defined 252 



Views of Mather and Rogers on the Taconic rocks .... 254 



Rogers and Safford on the primal rocks of Virginia and Tennessee . . 255 



Relations of the Taconic to the Champlain division .... 256 



The organic remains of the Taconic rocks 257 



The rocks of the so-called Quebec group 259 



The Red sand-rock of western Vermont 260 



Lower palaeozoic rocks of Labrador and Newfoundland . . . 261 



Lower palaeozoic rocks in the Champlain and Mississippi valleys . . 261 



Note on the palaeozoic formations in the Rocky Mountains . . . 262 



Stratigraphical breaks in the lower palaeozoic series 263 



Continuation of the Taconic controversy 264 



The Upper and Lower Potsdam of Billings 266 



Lower palaeozoic rocks of Europe 266 



Identity of Taconic with Lower and Middle Cambrian .... 268 



The Huronian or Urschiefer distinct from Cambrian .... 269 



Crystalline schists of Anglesea and the Rhine 270 



Crystalline rocks of the Scotch Highlands 271 



Comparative studies of crystalline formations 272 



Crystalline schists of Lakes Huron and Superior 274 



The crystalline schists of the Appalachians, pre-Cambrian . . . _7-i 



Credner on the Eo/oic formations of North America .... 277 



History of the Norian or Labrador rocks 279 



Relations of the various crystalline formations 281 



Hitchcock on the geology of the White Mountains 282 



PART II. THE ORIGIN OF CRYSTALLINE ROCKS. 



Mineralogy of the two classes of crystalline rocks .... 283 



Theories of the source of eruptive rocks 284 



