r ^ f 



Published monthly by tht: 



New York State Education Department f ^ ^ '*X^^J 



BULLETIN 353 



OCTOBER 1905 



New York State Museum 



John M. Clarke Director 



X^ 



Bulletin 95 

 GEOLOGY 9 



GEOLOGY 



OF THE 



NORTHERN ADIRONDACK REGION 



BY 



H. P. GUSHING 



PAGE 



Introduction 271 



Summary of geologic history. . . 272 



Precambric history 273 



Early Paleozoic history 2.79 



Later Paleozoic changes of level. 285 



Paleozoic disturbances 286 



Paleozoic igneous activity 287 



Paleozoic erosion 288 



Mesozoic history 289 



Cenozoic history 290 



Glacial history 292 



Postglacial history 293 



The rocks 294 



Precambric rocks 294 



Paleozoic rocks 354 



Rock structures 399 



Foliation , 399 



Folds 402 



Paleozoic rocks {continued) 



Faults 403 



Joints 412 



Topography 416 



Introduction 416 



Prepotsdam topography 418 



Paleozoic topography .419 



Appalachian uplift 421 



Mesozoic base-leveling 423 



Peneplains 425 



Main axis of elevation 427 



Lake belt 429 



Faults as topographic features. 430 



North plain 433 



Northern hills and valleys 434 



Streams '437 



Lakes 445 



Index 449 



ALBANY 



^ \(\^^s^ 



NEW YORK STATE EDUCATION DEPARTMENT 

 1905 



Mi49m S4-2000 Price 30 cents 



