﻿THE FAUNA AND STRATIGRAPHY OF THE 



JEFFERSON LIMESTONE IN THE NORTHERN 



ROCKY MOUNTAIN REGION* 



BY 



EDWARD M. KINDLE 



CONTENTS 



Introduction 



Nomenclature 



Areal Distribution and Stratigraphic Details 



Extent of formation 



Sections in Montana 



Sections in Wyoming 



Devonian rocks in Idaho 



Sections in Utah 

 Correlation 



Previous correlations 



Evidence of the fauna 

 Description of the Fauna 



Explanation of plates 



Introduction 



The considerable thickness of the Jefferson limestone in Mon- 

 tana, in many places approaching iooo feet, together with its 

 rather wide distribution gives the formation an important role 

 in the areal geology of Montana and adjacent states to the south. 

 Its importance as a mountain-making formation is perhaps next 

 to that of the Madison limestone in the Paleozoic of the northern 

 Rocky Mountain region. Owing to the scarcity of fossils in it our 

 knowledge of the age of this formation has remained very scanty 

 and uncertain. 



The principal objects of the field work on the Jefferson lime- 

 stone were to determine the. age of the formation and to get a 

 general conception of its extent and a knowledge of the fauna 



"Published bv permission of the Director of the U. S. Geological Survey. 



