THE LOMBARD OVERTHRUST AND RELATED GEO- 

 LOGICAL FEATURES 



WINTHROP P. HAYNES 

 Harvard University' 



CONTENTS 



Topographic and Structural Features 

 Folds 

 Faults 



The Lombard Overthrust 

 A Normal Fault 

 Stratigraphic Geology 

 Pre-Cambrian 



Spokane Formation 

 Empire Shale 

 Paleozoic 



Cambrian 



Absence of Ordovician and Silurian Strata 



Devonian 



Jefferson Limestone 

 Three Forks Formation 

 Carboniferous 



Madison Limestone 

 Quadrant Formation 

 Mesozoic 

 Tertiary 

 Pleistocene 

 Igneous Rocks 

 Granite 

 Diorite 

 Diabase 

 Summary 



TOPOGRAPHIC AND STRUCTURAL FEATURES 



The region involved in this discussion lies near the head of the 

 Missouri River in Montana. The chief topographic features are 

 hilly dependencies of the Little Belt Mountains. 



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