1878.] 277 [Hunt. 



ties above named, are found traversing alike the crystalline schists 

 and the granites of the region, which are probably eruptive masses 

 newer than the schists. To the Huronian he also refers the similar 

 crystalline rocks of the Coast range of California, as seen near San 

 Francisco and in the vicinity of San Jose. 



Referring then to the Atlantic belt, and to the South Mountain in 

 Pennsylvania, the speaker mentioned that in the continuation of this 

 range between the Susquehanna and the Potomac, the Laurentian 

 gneisses are concealed beneath strata referred to the Huronian, in- 

 cluding a great development of petrosilex rocks, often porphyritic. 1 

 Rocks of Montalban and Huronian age are met with along the line of 

 the Baltimore and Ohio R. R. ; but at Bellisle near Richmond, 

 Virginia, he had recognized the characteristic gneisses of the Lau- 

 rentian. 



He then gave a preliminary account of some late observations 

 made in a journey across the Blue Ridge in Mitchell county, North 

 Carolina. The gneisses of Roan Mountain, and the similar rocks at 

 its western base, which include large masses of very pure magnetic 

 iron ores, are Laurentian, but indications of a belt of Huronian 

 schists, with steatite, unctuous mica-schists, and specular iron ore, 

 were met with along the western flank of the mountain. To the 

 eastward, the Laurentian gneisses are succeeded by a great breadth 

 of thin-bedded gneisses, with highly micaceous and hornblendic 

 schists, referred by the speaker to the Montalban series, in which is 

 included the narrow belt of dunite or olivine rock found on the line 

 of section near Bakersville. These Montalban strata are intersected 

 by numerous endogenous granitic veins, which are extensively worked 

 for mica, and yield, moreover, fine cleavable masses of orthoclase 

 and of albite, together with beryl, apatite, and the rarer minerals, 

 autunite and samarskite. The rocks of this series, often decomposed 

 to considerable depths, were found to occupy the greater part of the 

 country as far east as Salisbury, interrupted however, near States- 

 ville, on the Western North Carolina R. R., by granitoid gneisses 

 which have the characters of the Laurentian. 



The belt consisting of granular quartz rock, with limestone and 

 hydrous mica-slates which was seen by the speaker at the eastern 

 base of the Blue Ridge on the Catawba river, near Marion, has all 

 the characters of the Lower Taconic, to which it was long since re- 



1 Proc. Bost. Soc. Nat. Hist., Vol. xvn, page 509. 



