5 NEW YORK STATE MUSEUM 



of our knowledge of this ancient region was laid by Dr Ebenezer 

 Emmons in 1836-42, when State Geologist in charge of the second 

 geological district. For fifty years after his day no systematic 

 effort was made to elucidate the intricate geological problems of 

 the region, but in 1891 a closer study was organized by the State 

 Geologist and the field was entered by Prof. James F." Kemp, 

 Prof. Charles H. Smyth, and Prof. Henry P. Gushing, with their 

 associates. All these geologists have maintained to the present 

 time their active interest in the mountain region, and to them, their 

 associates and successors we owe our present understanding of 

 Adirondack geology. The writer has been for ten years a worker 

 in this field under the auspices of the State Geological Survey. 



INTRODUCTION 

 Some General Principles of Earth History 



The observer who looks out over the Adirondack region sees a 

 great variety of physical features and, unless he has given some 

 study to the subject, is very likely to regard these as practically 

 unchangeable, and to think that they are now essentially as they 

 were in the beginning of the earth's history. But the physical 

 features of the Adirondacks, as we behold them today, represent 

 merely a single phase of a very long continued history. As a 

 result of the work of many able students of earth science during 

 the past hundred years, it is now well established that our planet 

 has a clearly recorded history of many millions of years, and that, 

 during the lapse of those eons, revolutionary changes in geography 

 have occurred, and also that th-ere has been a vast succession of 

 living beings which, from very early times, have gradually passed 

 from simple into more and more complex forms. The geographic 

 changes and the organisms of the past ages have left abundant 

 evidence of their character, and the study of the rock formations 

 has shown that within them we have a fairly complete record of 

 the earth's history. While it is true that very much yet remains 

 to be learned about this old earth, it is a real source of wonder- 

 ment that man, through the exercise of his highest faculty, has 

 come to know so much concerning it. 



Geology, meaning literally "earth science," deals with the history 

 of the earth and its inhabitants as revealed in the rocks. This 

 science is very broad in its scope and treats of the processes by 

 which the earth has been, and is now being, changed ; the structure 

 of the earth ; the stages through which it has passed ; and the evo- 

 lution of the organisms which have lived upon it. 



