y2 THE PENOKEE IKON BEARING SERIES. 



whole more prevalent in the deposits near the foot-wall quartzite. This 

 peculiarity is subsequently used in the explanation of the origin of the 

 ores. 



Lawton ((JhakleS I).). The Gogebic Jnm Raiise. Annual Reixnt of the Com- 

 missioner of Mineral Statistics of the State ol' Michigan for l.SS(i. Lansing', 1887. 

 l.p. 1L'5-I(i5. 



Tlii.s report contains a full account of the rapid development of tlie 

 mines on this range during the year 1880. It describes in detail each af the 

 important ore-producers, and also refers to the more promising prospects. 

 Already several of the mines have been developed sutficienth" to show that 

 they contain large deposits of ore. While this report is of great economic 

 value, it adds comparatively little to the preAnous knowledge of the geology 

 of the di.strict. 'I'hc fact that the dike-rocks have a tendency to undercut 

 the ore-bodies is noticed, but the generalization as to their genetic relations 

 was not reached. 



1S88. 



Lawton (Charles D.). The Gogebic Inm Range. Annual Report of the Com- 

 missionei- of Mineral Statistics of tlie State of Michigan for ISST. tjansing, ISSH, \)\). 

 90-114. 



Mr. Lawton's i-e])ort for 1888 records the collapse which followed the 

 great speculative excitement of the previous year. Not\\ithstanding the 

 abrupt termination of speculation, the product of iron ore from the i-juige is 

 as large as in the previous year. Detailed accounts are given of additional 

 developments in each of the iron mines, and their condition. The fact that 

 the dike-rocks form the nortliern liasement of the iron-oiv deposits is noted 

 of (juite a number of the mines. In the description of the Xorrie mine it is 

 said, "the foot-wall flattens oixt and extends a o-reat distance north, carrN ino- 

 the ore-body with it." Whether this is due to a fault in the foot-wall at 

 this point, or oid\ represents tlie irregular configuration of the surfa<-e of tlie 

 coimtry at the end of the accumulation of the Quartz-slate meiiilier is not 

 explained. 



BiRKiNBiNK (.loiTN). Iron Ore Mining in 1887. IT. S. Geological Survey, ,T. 

 W. Powell, Director. .Mineral Resources of tiie l'nite<l States for 1887: David T. 

 Day, Chief of Division of Mining Statistics and Technology, pp. 30-57. 



