GEOLOGICAL EXPLORATIONS AND LITERATURE. 95 



This additional account by Mr. Birkinbine of the de\ ehipineut of the 

 rang-e is accurate, and from it the following- quotations are made: 



If Mie development of the Veriniliou iron-ore district is startling, that of tlie 

 Gogebic iron range in Wisconsin and Micliigan is even more so; for, altliougli tlie 

 existence of visible outcrojis of ore was long known, and considerable amounts of 

 money were exjiended by some of our large iron companies, no actual exploitation can 

 be considered as having been made until the year ISS.'j, when railroad connections 

 were comjileted to Asldand and dock facilities provided. During 1S.S4 1,022 gross 

 tons were sent from what is now the Gogebic region, but in 1885 this amount was 

 increased cnoi-mously, and the shipments amounted to 119,760 gross tons; and in 

 1886, 756,281 gross tons were sent to market. . . . 



The development along the a[)]>arent strike of the ore covers nearly twenty 

 miles in length, and active exploration is in progress for as great a distance both 

 east and west of this territory, and also ui)on a parallel ridge 12 miles stmtli, the 

 latter being for magnetic ore. Thecenter of the present devcloiied iron-ore jiroperties 

 is near to the Montreal river, which forms the boundary between Wisconsin and 

 Michigan; the largest ])r()duct'i's uji to tiie iirescnt time are, however, chiedy in the 

 State of Michigan. 



The ores in the Gogebic range ditt'ei- from tliose of the Vermilion range in being 

 softer, and therefore more easily mim-d, yielding less iron and also less phospliorus, 

 but carrying a greater ju'rcentage of manganese, and more moisture. The dij) of the 

 Vermili<m ore is nearly vertical; that of the Gogebic, ores approximately 70°. 



The ores of tlie Gogebic range evidently lie in a series of lenses, often connected 

 or in echelon, and the i-egion has attained considerable notoiiety from the fact that 

 ore indications or actual deposits have been found upon nearly every property ahmg 

 the ajiparent strike of the vein matter. 



Tlie general geology of the district is explained by Mv. J. Parke Chanuing, of 

 Bessemer. He says: "The chief characteristic of the Gogebic range, and that which 

 makes it so easy to ex|)lore, is the regularity and persistency of tlie formation and 

 the strongly marked character of the footwall, which dips from 45 to 70 degrees to 

 the north, being tiattest near »Snnday lake. The sinking of a shall on tlie North 

 Aurora, which it is thought will reach the continuation on the Aurora vein at a depth 

 of about 1,200 feet, will illustrate the faith in its persistcnc,\'. 



"Their magnitude (aside from the occurrences of horses and fluctuations in their 

 width) has been aft'ected in at least one instance by a dike which cuts clear across the 

 vein. In a few cases dikes of this dcscri]ition have been sunk through, and the ore 

 found under them. Faults of the entire formation have been sus|»ected in one or two 

 localities, but are not directly iiroveii." . . . 



The (iogebic ores carry, on an a\ eiage, about 00 per cent of iioii when dry, some 

 of the mining being above that tigure. Carelessness in mining, particularly in open 



