572 M. AU ROUSSEAU AND HENRY S. WASHINGTON 



showing affinity with the rocks of a dominantly sodic zone or 

 comagmatic region which finds expression in the eastern United 

 States from New England to Texas.- 



The large mass of nephelite syenite situated to the northwest 

 of Beemerville was first described in detail by Emerson, who 

 recognized its true character and described it microscopically. 

 He believed the mass to be a large dyke.^ Emerson also described, 

 under the name of mica-diabase, the series of dykes penetrating 

 the ore-bodies at the Buckwheat Field at Franklin Furnace.^ 



Kemp examined the mass known as Rutan's Hill, which forms 

 a prominent landmark east of the northern end of the main mass 

 of nephelite syenite at Beemerville, and described it as a boss of 

 porphyrite, giving two analyses of the rock, and one of the biotite 

 isolated from it.^ He also recognized the nature of a number of 

 similar "bosses" to the southeast of the main mass, south of 

 Beemerville and Plumbstock. On a more detailed investigation 

 Kemp mapped and described the main mass and its immediate 

 satellites, demonstrating clearly the inhomogeneity of the Beemer- 

 ville nephelite syenite and proving the occurrence of a nephelite 

 porphyry, probably as a dyke, within it. Here also he showed 

 that the satellitic bosses are basic alkalic rocks, allied to the ouachi- 

 tites and fourchites. He provided two analyses of different facies 

 of the nepheHte syenite and one of the nephelite porphyry. ^ These 

 investigations established the fact that the Beemerville mass and 

 its associates resemble the rocks of the Magnet Cove complex, 

 Arkansas. 



Kemp next examined a basic dyke two miles northwest of 

 Hamburg, and from microscopical investigation, and the analysis of 

 certain pseudomorphous spheroids which it exhibited, he offered 

 the tentative suggestion that the rock was a leucite tephrite, and 

 concluded that it was related to the Beemerville nephelite syenite.^ 



' H. S. Washington, Jour. Franklin Inst., CXC (1920), p. 796. 

 ^ B. K. Emerson, Amer. Jour. Scl., XXIII (1882), p. 302. 



3 Ibid., p. 376. 



4 J. F. Kemp, Amer. Jour. Sci., XXXVIII (1889), p. 130. 



5 J. F. Kemp, Trans. N.Y. Acad. Sci., XI (1892), p. 60. 

 * J. F. Kemp, Amer. Jour. Sci., XLV (1893), p. 303. 



