146 THE MARQUETTE IRON-BEAKING DISTRICT. 



chlorite-schists, clay-slates, graywackes, conglomerates, aud quartzites. He 

 also states that the greenstone knobs in the neigliborhood of Negaunee are 

 outliers of the greenstone-schists, older than the iron-formation rocks by 

 which they are surrounded; but he cites no proofs of the correctness of this 

 statement. 



Dana, J. D. Manual of geology. Fourtli edition. American Book Company, 

 1895. 



Professor Dana, in the last edition of his Manual, declines to recog- 

 nize the Algonkian system as distinct from Archean. He places the Mar- 

 quette ores in the Hurouian as recognized by Logan and Murray, and 

 accepts the conclusions of Irving and Van Hise as to their origin from a 

 carbonate by metaniorphism (pp. 449-450). 



RoMiNGER, C. Geological report on the Upper Peninsula of Michigan, exhib- 

 iting the progress of work from 1881 to 1884. Iron and copper regions. Geol. Surv. 

 of Michigan, Vol. V, Lansing, 1895, jiages 1-94. 



This is the long-delayed report by Rominger on the iron and cojjper 

 districts of Michigan, to which reference has ali'eady been made several 

 times. In justice to its author it should be stated that the work upon which 

 it is based was done in the years 1881 and 1882, and the manuscript was 

 completed in May, 1885, but the publication was deferred for the reason, 

 given in Rominger's own Avords, that " the description of all the results 

 obtained comprises the space of about 50 or 60 printed pages, too small for 

 a se^^arate publication in book form." It was not until the fall of 1893 that 

 enough additional material had been accumulated by the Michigan survey 

 in proper shape to be incorporated with Rominger's report and make a 

 volume of sufficient size to warrant its publication by the State board of 

 geological survey. 



The report is a continuation of that of 1881. Some of the conclusions 

 reached in it are different from those reached in the previous report, but on 

 the whole the author maintains his original position with respect to most 

 of the disputed points. He still declines to regard the Marquette rocks 

 as comprising portions of two distinct series, as "no tenable line of 

 demarcation between an older Lam-entian and a younger Huronian group 



