Eggleston — Eruptive Rocks at Cutting sville, Vt. 377 



Art. XXV. — Eruptive Rocks at Cutting sville, Vermont;* 

 by Julius Wooster Eggleston. 



Introduction. 



Topography. 

 Conditions of Exposure. 

 Outline of field relations. 

 Country roeks. 

 Eruptive roeks. 



Composite stock. 

 Smaller igneous-rock areas. 

 Breccia mass. 

 Dikes. 

 Date of Eruptivity. 

 Petrography. 



Country rocks. 

 Gneisses. 

 Limestone. 

 Quartzite. 

 Schists. 

 Stock rocks. 



Essexite. 



Hornblende-biotite syenite. 

 Pulaskite. 



Sodalite-nephelite syenite. 

 Augite syenite (nordmarkite). 

 Dike rocks. 



Essexite porphyry. 

 Nephelite syenite. 

 Syenite porphyry. 

 Zircon-rich pulaskite porphyry. 

 Aplite. 

 Tinguaite. 

 Camp ton ite. 

 Mineral Deposits. 

 General Conclusions. 



Emplacement of eruptives. 

 Comparison with other areas. 

 Order of eruption. 

 Origin of the Magmas 

 List of chemical analyses. 



INTRODUCTION. 



Under the name "granite" the eruptive body at Cut- 

 tingsville, on the west slope of the Green Mountains and 

 10 miles southeast of Rutland, Vermont, was noted in E. 

 Hitchcock's geological report on Vermont (map and vol. 

 2, p. 742, 1861). In 1892 and 1894 Mr. C. L. Whittle, 

 with an assistant, studied the Cuttingsville area for the 

 U. S. Geological Survey, but the results of this work 

 have not been published. In the years 1906 to 1909 the 



* Shaler Memorial Investigation No. 9. The cost of publication of this 

 paper has been defrayed by the Shaler Memorial Fund, Harvard University. 



