TABLE OF FIELD ASSOCIATIONS 95 



Table showing Field Associations of Alkaline and Subalkaline Erupti res— Contumed. 



Region. 



Alkaline eruptives. 



Associated subalka- 

 line eruptives. I 



Carbonate rocks cut by 

 alkaline eruptives. 



Black Hills, South 

 Dakota. 



Phonolite, grorudite. 



Diorite, liparite. 



Ditto. 



Denver Basin, Col- 

 orado. 



Trachydolerite. 





Mesozoic limestones 

 of four horizons. 



Rico District, Col- 

 orado. 



Monzonite. 





Paleozoic limestones 



La Plata Quad- 

 rangle, Colorado. 



Monzonite. 





Paleozoic and Juras- 

 sic limestones, 

 calcareous s a n d- 

 stones, etcetera. 



Telluride Quad- 

 rangle, Colorado. 



Monzonite. 





Ditto. 



Georgetown Quad- 

 rangle, Colorado. 



Alkali syenite por- 

 phyry, latite, bos- 

 tonite, etcetera. 



Diorite, granite, 

 etcetera. 



Pre-Cambrian lime- 

 stone. 



Cripple Creek Dis- 

 trict, Colorado. 



Phonolite, latite- 

 phonolite, s y e - 

 nite, trachydoler- 

 ite, vogesite, mon- 

 chiquite. 



Granite, olivine 

 syenite, anor- 

 thosite, diabase 



? 



Spanish Peaks, 

 Colorado. 



Monzonite por- 

 phyry. 





Mesozoic and prob- 

 ably Paleozoic; 

 limestones a n <1 

 calcareous shales. 



Magnet Cove, Ar- 

 kansas. 



Nephelite syenite, 

 ijolite, shonkin- 

 ite, leucite por- 

 phyry, tinguaite, 

 monchiquite, ja- 

 cupirangite. 





Paleozoic magne- 

 sian limestones. 



Walsenburg Quad- 

 rangle, New Mex- 

 ico. 



Monzonite por- 

 phyry. 





Ditto. 



