ELISHA MITCHELL SCIENTIFIC SOCIETY. 60 



(6) " Greenish, and full of cavities, and frequently epi- 

 dotic. 



(7) "Banded quartzite, or coarsely agfatized. 

 "These fonrs of quartzite are not confined to 



rocks of a particular aire, or to a t^-iv^en series. They 

 seem to be distributed throuijh "formations of all ages and 

 epochs. They are common to both divisions of the Ta- 

 conic. " 



Emmons explains their ori^jfin from an aqueous chem- 

 ical standpoint.' 



KERR's HURONIAN system IN CENTRAL NORTH CAROLINA. 



Kerr reco^rnized five principal outcrops of the Huronian 

 rocks. The one that corresponds to the Central Slate 

 belt, and hence of interest here, is stated to lie on the 

 west side of the Ralei^-h n'ranite.' "The bottom beds 

 are aro'illaceous and talcoid.^ " """ Three or four miles 

 from RaleijO-h these slates become hi^-hly plumbag-inous, 

 * "^ "^^ and a heavy body of micaceous, white, slaty quartz- 

 ites follows closely alon<>- the west side of the ^raphite. 



Alternations of aroillaceous, talcoid and quartzitic beds 

 continue for live or six miles, when they disappear be- 

 neath a narrow trough of Triassic sandstones, beyond 

 which they emerge along an irregular, but approximately 

 northeast and southwest, line in the central mineral beai'- 

 ing slate belt. " '' "" This tract extends quite across 

 the State in a breadth of 20 to 40 miles, and is composed 

 of siliceous slates and clay slates chiefly; the former being 

 often brecciated and conglomerate, the pebbles sometimes a 

 foot and upwards in diameter, frequently chloritic, and 

 often passing into hornstone and chert, and occasionally 

 into quartzite. The clay slates are generall}^ thin-bed- 

 ded, often shaly, gray, drab, banded, blue and frequently 

 greenish from an admixture of chlorite; sometimes tal- 



1 Ibid. pp. 51 and 72. 

 5 Report of the Geol. Sur. of N. C, 18 ro, Vol. 1. pp. 181-9, 



