TflE MAKQUETTE IROXBEARING DISTRICT. 



The work of the fii'st ])erio(I was mainly i)reliniiiiar}'. It beji'an with 

 the general notes of the early na\ngators and explorers, and ended with the 

 statement of the general features of the Marquette geology as given in 

 Foster and Whitney's report. This was a period of great activity. It 

 included the writings of the navigators or explorers, Schoolcraft and Bay- 

 field, of the first State geologist of Michigan, Dr. Houghton, and of the 

 United States surveyoi's and geologists, Cunningham, Gray, Locke, Ohan- 

 ning, Burt, Hulibard, Jackson, Foster, and Whitney. The various reports 

 made were devoted to a g-eneral discussion of the geology of the district 

 and to the classification of the rocks found. 



The second jx-riod was not so fruitful of results. The onK- notalde 

 jjaper published during this time was that of Kimball, which appeai-ed in 

 1865. Whitney, Rivot, Whittlesey, Hunt, Bigsby, and Credner also cou- 

 tril)uted to the discussion. Very little that was new was added to the 

 knowledge* of the region, the principal articles, with the exception of the one 

 by Kimball, being in confirmation or in contradiction of the various jioints 

 raised b}' ilessrs. Foster and Whitney — mainly with respect to the di\isi- 

 bility of the "Azoic" series. In Kimball's ai'ticle the sequence of the rock 

 beds in several portions of the iron range is noted, and a theory of the 

 origin of the iron ores, in opposition to that advanced by P^oster and 

 Whitney, is advanced. 



Tlie third period was again a tiuie of activity, made so through the 

 efforts of tlie Michigan and Wisconsin surveys. Alexander Winchell, 

 Brooks, Julien, Wright, Wichmann, and Rominger contributed to the State 

 reports, while Wailsworth, Crosby, and others published in the various 

 journals. In this period the publications took ;i much wider range than in 

 preceding jjcriods. Brooks and Rominger each published lengthy reports 

 dealing with the general geology of the entire district. Detailed descrip- 

 tions of observations are the rule in all the jjapers written, and the con- 

 clusions are based on these. In this period also the first detailed maps of 

 the mining region were made. In general the principal work done was the 

 recording of accurate observations. This period is also noted for the vigor- 

 ous controversy that arose between the advocates of the theory which 

 ascribed to the jaspers and ores of the region an ei'uptive origin and the 



