AMERICAN GEOLOGISTS AND NATURALISTS. 35 



ported to any distance, but to belong to the rocks in their immediate 

 neighborhood. 



He asked attention to the subject of the deposit gold mines ; whe- 

 ther these were not still in progress of formation, notwithstanding 

 the opinions to the contrary found in many of the foreign treatises ; 

 mentioning their occurrence always near the veins of the ore, and of 

 the fact of veins having been discovered by working the deposits 

 up to them, above which the gold suddenly ceased. Of the power 

 of the freshets, the discovery of the little buried village in Nacochee 

 Valley, Ga., was mentioned as a remarkable evidence. His opinion 

 was, that though many of the deposits referred themselves far back 

 to the period when the whole country Avas overspread with diluvium, 

 still that the deposits have been going on ever since. Specimens 

 were shown from, and some remarks made concerning, the gold and 

 copper ores of Davidson and Guilford counties, N. C. Veins orig- 

 inally worked for the former, gradually passed into lodes of sul- 

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

 the veins at the surface. Rich specimens of the double sulphnrets 

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

 mine the lode is over ten feet thick, for the depth of one hundred 

 and five feet, and consists 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 originally worked for lead, the ore being a carbonate, very rich, 

 and in beautiful 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. All 

 the metalliferous veins, it is beheved, are found at the point of con- 

 tact 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 fii-st 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 Michigan. 



He began by remarking, that that portion of Michigan lying be- 

 tween 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 dis- 

 tance of one hundred and fifty miles, consist of a series of fossil- 



