564 DEPARTMENT OF THE INTERIOR 



2 GEORGE V., A. 1912 



TABLE XXXVII.— PRINCIPAL EVENTS RECORDED IN THE WESTERN 

 GEOSYNCLINAL BELT AS A WHOLE. 



Pleistocene Local vulcanism. 



Glaciation. 

 Pliocene Local vulcanism. 



Fresh-water sedimentation. 



Local orogenic movement ; local unconformity. 



Miocene Local batholithic intrusion. 



Widespread vulcanism. 

 Fresh-water sedimentation. 

 Local marine sedimentation. 



Local orogenic movement ; local unconformity. 



Oligocene Local vulcanism. 



Fresh- water sedimentation, 



Local Eocene Geosyn- j Eocene Fresh- water sedimentation. 



.Local vulcanism. 

 I Coastal marine sedimentation. 



General orogenic movements and widespread unconformity. 



( Upper Cretaceous Local vulcanism. 



Coastal and other marine sedimentation. 

 Local Cretaceous Geo- j Local orogenic movements and local unconformity. 



synclinals. j Lotver Cretaceous Coastal and other local marine sedimentation. 



Local vulcanism. 

 L Local batholithic intrusion (Upper Jurassic ?) 



Widespread unconformity. 



(Jurassic Widespread batholithic intrusion. 



Local vulcanism. 

 Widespread Jura-trias \ Local ( wid ^pread ?) marine sedimentation. 



Geosynclinal. General orogenic movements (late Jurassic). 



| Triassic Widespread marine sedimentation (general ? ). 



I Relatively widespread vulcanism. 



Probably ividespread though not energetic crustal movements 

 and local unconformity. 



( Pennsylvanian General marine sedimentation. 



Very widespread vulcanism (general ?). 

 i 



General subsidence in Western Geosynclinal Belt ; simul- 

 General Carboniferous { taneous general uplift in Eastern Geosynclinal Belt 



Geosynclinal. except in its southern third. 



Mississippian Local marine sedimentation. 



Local vulcanism. 



Local crustal movements and unconformity. 



( Devonian Local marine sedimentation. 



General Erosion in Local vulcanism. 



Western Belt, with i Silurian Local marine sedimentation. 



Formation of Rocky -{ Local vulcanism. 



Mountain Geosyncli- I Ordovician Local marine sedimentation. 



NAL. I Cambrian ? General erosion. 



{^Beltian ? General erosion in later part. 



