88 Copper and Silver of Kewenaw Point, Lake Superior, 
as large as pistol and musket balls occur in trapezohedral forms. 
Some of them are very perfectly crystallized. The best specimen 
I have, was given me by Mr. Jacobs, one of the explorers of mines 
on Kewenaw Point. 
Native copper is disseminated in the trap rocks and in most of 
the veins of other minerals found near it, but it is far more abun- 
dant in the amygdaloid, and not unfrequently fills the cavities in 
that rock. Isolated masses of many pounds weight are occasion- 
ally found, when the rock has undergone decay ; and all the loose 
bowlders of metallic copper which are found at the mouths of the 
rivers and on the lake shore on Kewenaw Point, were derived from 
the amygdaloidal trap. The great copper rock found on the On- 
tanagon river, is an erratic bowlder, which was transported to that 
spot during the drift epoch, and originally was included in ser- 
pentine, arock very different from any found in the Ontanagon 
district. Since the only known deposit of copper in serpentine 
is on Isle Royale,* and that island is nearly north from Ontana- 
gon river, or in a direction from which the drift current came, it 
is supposed that it originated on that island and was transported 
in ancient times to the southward by an ice raft, which deposited 
it as a drift bowlder on the spot where it was found. I have not 
visited that locality, but form this opinion from the best informa- 
tion I could obtain.. This great copper rock is now deposited at 
Washington, D.C. and is in possession of the Government. This 
enormous mass of metal, weighing between two and three 
thousand pounds, is well calculated to inspire too strong ex- 
pectations of obtaining valuable mines on the coast of Lake Su- 
perior, and those who have such hopes shonld be warned that 
masses of metallic copper of that magnitude are great raritiesyif 
indeed there is another like it in the whole country. _ Native cop- 
per is rarely a favorable sign in mines, and it is looked upon favor- 
ably only when it is so abundant as to constitute a considerable 
part of a large vein, or when it is pretty uniformly mixed with the 
rock. There are a few such localitieson Kewenaw Point, and those 
I have examined with great attention. There are nine veins of 
native copper already discovered on the locations leased to: the 
Lake Superior Copper Mining Company. Of that number only two 
* Dr. Locke is of opinion that the mineral supposed to be serpentine is ug 
I have not examined it, 
