-.^ ^r- 



476 



THE AZOIC SYSTEM AND ITS SUBDIVISIONS. 



ward, in the counties of Floyd and Carroll, I could find no typical Huronian, 

 such as the chlorite rocks, the felsite, &c." 



Throughout the whole of this communication it appears clearly that 

 Profc&sor Fontaine considers that the terms Huronian and Laurentian 

 are simply names for certain lithologically peculiar rocks. Chlorite 

 schists are called "typical Huronian," and gneisses " Laurentian" ; but 

 it is easy to see from his description that the two, with the other ordina- 

 rily associated rocks, occur together, sometimes one predominating and 

 sometimes another, in a manner perfectly characteristic of the Azoic 

 series as a whole, yet utterly in opposition to their existence as sepa- 

 rate and distinct systems. 



NOKTH CAROLINA. 



In the Report of Prof. W. C. Kerr on the Geology of North Carolina 

 (1875), a large portion of the rocks of that State is assigned to the 

 Laurentian and Huronian formations. Three distinct belts of Lauren- 

 tian are recognized. The eastern one 



"consists of light colored and grey gneisses, whioli oGcasionally pass inio gran- 

 ite, but more frequently into fclspathic, quartzose (and rarely hornhlendic) 

 schists. In some localities the mica is entirely wanting, and then the rock is 

 either a dull-reddish, brownish, or whitish massive felspathic rock, trachyte, 

 euryte, felspar porphyry, &c." (I c, p. 122.) 



The Edgecombe granite, which Professor Kerr regards as a metamor- 

 phosed sedimentary rock (gneiss), " shows no gneissic or foliated struc- 

 ture, being undistinguishable from true granite." 



In the second area {L c, pp. 123-128), 



" the characteristic and prevalent rocks are syenyte, doleryte, greenstone, am- 

 phibolyte, granite, porphyry, and trachyte .... The most common rock is of 

 a hornhlendic character j and traps, trachytes, granulytes and porphyries are 

 confusedly and angularly wedged in among each other, with i'reciuciLt veins of 



epidote crossing the felspathic species in every direction The absence of 



anything hke stratification or foliation is conspicuous throughout the region. 

 .... If there be any significance in structure or in lithological characters, 

 this singular body of rocks seems entitled to be placed at the very base of the 

 Archcean age, certainly at the bottom of the Laurentian ; and even below 

 these, if there be any older rocks exposed anywhere, — the true Azoic or 



