92 



R. A. DALY ORIGIN OF THE ALKALINE ROCKS 



sometimes clear, too, that limestones were present in the roofs of alkaline 

 intrusives of the stock or batholith order, and it is then legitimate to 

 consider such limestone as subject to stoping and abyssal assimilation 

 during intrusion. The blanks in the third column mean lack of infor- 

 mation and not necessarily absence of subalkaline eruptions in the corre- 

 sponding districts. 



Table showing Field Associations of Alkaline and Subalkaline 

 Eruptives and Calcareous Sediments 



NOETH AMERICA 



Region. 



Alkaline eruptives. 



Associated subalka- 

 line eruptives. 



Carbonate rocks cut by 

 alkaline eruptives. 



Bancroft, Ontario. 



Nephelite syenite. 



Anorthosite, gran- 

 ite, etcetera. 



Grenville limestone. 



Monteregian Hills, 

 Quebec. 



Theralite, essexite, 

 pulaskite, nord- 

 markite, nephel- 

 ite syenite, camp- 

 tonite, boston ite, 

 tinguaite, solvs- 

 bergite, fourchite, 

 monchiquite, al- 

 noite. 



Gabbro, diabase, 

 etcetera. 



Chazy, Trenton, and 

 Devonian lime- 

 stones. Pre-Cam- 

 brian limestone. ? 



Ottawa Valley, 

 Quebec. 



Shonkinite. 



Granite, diabase, 

 pyroxenite, et- 

 cetera. 



? 



Pooh-bah Lake, 

 Ontario. 



Malignite. 



Diabase, granite, 

 etcetera. 



? 



Port Cold well, On- 

 tario. 



Nephehte syenite. 



Gabbro. 



? 



Heron Bay, Onta- 

 rio. 



Heronite. 



Diabase. 



? 



North-central Wis- 

 consin. 



Nephelite syenite, 

 etcetera. 



Gabbro, diorite, 

 granite, etcetera 



? Calcareous g r a y- 

 wacke, chert, shale, 

 and slate in older 

 terrane. 



Southwest Alaska. 



Leucite phonolite. 



Granodiorite, et- 

 cetera. 



Paleozoic limestones 

 beneath Jurassic 

 series. 



