Association of American Geologists. 183 



overspread with diluvium, still that the deposits have been going on ever 

 since. Specimens were shown from, and some remarks made, concern- 

 ing the gold and copper ores of Davidson and Guilford counties, N. C. 

 Veins originally worked for the former, gradually passed into lodes of 

 sulphuret of copper and iron, though these formed a very small part of 

 the veins at the surface. Rich specimens of the double sulphurets from 

 the Harlan mine, Guilford county, were exhibited, in which mine the lode 

 is over ten feet thick, or the depth of one hundred and five feet, and con- 

 sists almost entirely of these ores. 



Some account of King's silver mine, Davidson county, was given, and 

 specimens of the varieties of the silver ore shown. The mine was origin- 

 ally worked for lead, the ore being a carbonate, very rich, and in beauti- 

 ful crystals. Native silver was discovered, and the pig lead already made, 

 found to contain a considerable amount of that metal. Phosphate of lead, 

 copper, zinc and sulphuret of iron, were also mentioned as occurring in 

 the lode, which was twelve feet thick. Some of the ore was of a soft 

 light magnesian character, and though its specific gravity could not be 

 twice that of water, yet it was considered a rich silver ore. 



The lode lies between granite and a magnesian rock above. AW the 

 metalliferous veins, it is believed, are found at the point of contact of these 

 two rocks. 



Peter A. Browne^ Esq. presented to the Association a section 

 of the rock strata on the Schuylkill above Philadelphia, drawn 

 about the year 1825, being the first geological section made in 

 the state of Pennsylvania. 



Dr. Houghton then made some remarks upon the subject 

 of the metalliferous veins of the northern peninsula of Mich- 

 igan. 



He began by remarking, that that portion of Michigan lying between 

 Lakes Huron and Michigan on the south, and Lake Superior on the 

 north, is known as the upper or northern peninsula, while that portion 

 of the state lying south of the Straits of Mackinac, is more usually known 

 as the southern or lower peninsula. 



The rocks of the easterly portion of the upper peninsula, for a distance 

 of one hundred and fifty miles, consist of a series of fossiliferous limestones 

 and shales, resting upon sandstones, the whole dipping a few degrees east 

 of south. The limestones appear only on the southerly portion of the pe- 

 ninsula, while the underlying sand-rocks form the immediate coast of 

 Lake Superior. 



At a point very nearly one hundred and fifty miles west from the east- 

 erly extremity of the peninsula, and near to the immediate coast of Lake 

 Superior, several low ranges of granitic hills make their appearance, 

 which hills are flanked on the south, by quartz rock, alternating with 



