ON THE GEOLOGICAL STRUCTURE OF THE MOUNT 

 WASHINGTON MASS OF THE TACONIC RANGE. 



(With Two Plates.) 



Published with the permission of the Director of the United States 

 Geological Survey. 



CONTENTS. 



Introduction. 



Topography. 



Previous Work within the Area. 



Conditions and Progress of the present Investigation. 



Horizons Represented. 



Their Lithological Character. 



Canaan Limestone. 



Riga Schist. 



Egremont Limestone. 



Everett Schist. 

 Explanation of Map, Areal Geology. 

 Method of constructing Sections. 

 Structure of the Mountain. 



Variable Thickness of the Egremont Limestone. 



Metamorphic Character of the Rocks as indicated by Microscopic Studies. 

 Summary and Conclusion. 



That portion of the Taconic Range which is known as Mount 

 Washington is both topographically and geologically a unit. It 

 covers an elongated elliptical area, about fifteen miles in length 

 and four and one-half miles in average breadth, lying in the states 

 of Massachusetts, Connecticut and New York. It occupies the 

 entire township of Mt. Washington, and portions of Sheffield 

 and Egremont in Massachusetts ; about one-third of Salisbury 

 in Connecticut ; and portions of Northeast, Ancram, Copake and 

 Hillsdale in New York. 



Topography. — The Mt. Washington mass is a double ridge 

 enclosing a summit plain. Mt. Everett, or the "Dome of the 



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