28 



THE MARQITETTE IRON BEARING DISTRICT. 



geology of the irou-})r()(]uoiug district. Although iinpriuted with "The 

 Iron Region" on its title-page, the description of the iron region j)roper 

 occupies only about 95 pages of the report. 



The map accompanying the report is in general like that published 

 with the authors' earlier report (PI. II), though the colors have been 

 changed. Presque Isle has for some reason been colored as gi'anite, and 

 "basalt" has been left out of the scheme of colors. There are a few other 

 differences in the two maps, but in the main they are identical. 



The report is introduced by a tabular statement of the order of suc- 

 cession of the rocks existing Avithin the limits of the district studied. This 

 table as given b}' the authors (p. 2) is as follows: 



Classification of Ike rocks. 



Of these various divisions of rocks there are present in the region with 

 which we are now concerned the foUowini'-: the Potsdam sandstone of 



