XLbc journal of (Beolog^ 



SUPPLEMENT TO NOVEMBER-DECEMBER J9I5 



Vol. XXIII CONTENTS No. 8 



THE LATER STAGES OF THE EVOLUTION OF THE IGNEOUS ROCKS N. L. Bowen 



Introduction .-----.------- .-2 



Differentiation -.-------------------3 



The Association of Diabase and Micropegmatite ............. ly 



The Importance of the Formation of Biotite ..------------41 



The Crystallkation of Basaltic Magma .-.--.-.-..-.--46 

 Field Evidences of the Control of Crystallization in Differentiation .-------48 



The Alkaline Rocks --------------------55 



Is Basaltic Magma the Parental Magma of All Igneous Rocks? -----..--66 



The Normal Line of Descent -----.-----------74 



Summary and Conclusion --.--------.-------89 



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